JPH02127535A - Production of crimped polyamide yarn - Google Patents

Abstract

PURPOSE:To obtain the subject yarn, having a percentage crimp and spring constant comparable to those of crimped yarns for carpets produced by mechanical processing using production of natural crimps at a low cost by heat-treating a specific latent crimpable polyamide multifilament yarn under specified conditions. CONSTITUTION:The objective yarn obtained by heat-treating a latent crimpable polyamide multifilament yarn capable of providing a crimped yarn exhibiting >=80% crystal orientation degree measured by a wide angle X-ray diffractometry and >=50% crimp elongation ratio by heat treatment at 98 deg.C for 5min at >=150 deg.C under 1-10mg/d tension. The above-mentioned latent crimpable polyamide multifilament yarn is preferably obtained by using an apparatus composed of a spinning head 1, a spinneret 2, an aqueous solution feed roll 4 and a winding part 5 and selecting the take-off speed and application position of the aqueous solution, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] More specifically, the present invention relates to a method for producing polyamide crimped yarn. This invention relates to a method for producing polyamide cotton yarn suitable for carpets by subjecting latent crimpable polyamide multifilament obtained by a method based on the warp method to a specific heat treatment.

[Conventional technology]

By mechanical processing methods such as false twisting and pressing, crimped polyamide yarns such as nylon 6 and nylon 66 are produced in large quantities and are widely used in socks, carpets, and the like. However, manufacturing crimped yarn by these mechanical processes requires an expensive processing machine and a large amount of energy and manpower.

Therefore, the cost of the obtained crimped yarn is extremely high.

On the other hand, nylon 66 is disclosed in Japanese Patent Application Laid-open No. 57-154409
8. When spinning at high speeds of over 1,000 m/min, the resulting multifilament single yarn has a birefringence distribution in the radial direction by spinning via an aspirator between the spinneret and the winder. This is disclosed. However, in the nylon 66 multifilament obtained by this method, the birefringence distribution in the radial direction, that is, the interference fringes observed with a transmission interference microscope, are symmetrical with respect to the central axis of the single filament, and natural crimp occurs in principle. It's something that doesn't exist. Furthermore, this prior example does not describe or suggest natural crimp.

[Problem to be solved by the invention]

The present inventors previously disclosed in Japanese Patent Application No. 63-140505 that ``the interference fringes observed with a transmission interference microscope of a single yarn are asymmetrical with respect to the central axis of the single yarn, and were measured using wide-angle X-ray diffraction. We have proposed a naturally crimpable polyamide filament consisting of a single filament with a substantially circular cross-sectional shape, which has a degree of crystal orientation of 80% or more and can be crimped by heat treatment.

Furthermore, the present inventors have proposed in Japanese Patent Application No. 140504/1982 that, as a method for manufacturing polyamide filaments proposed in Japanese Patent Application No. 140505/1980, ``When manufacturing multifilament by melt spinning polyamide, While each filament was kept at a temperature of 150°C or higher, an aqueous liquid was applied to each filament from one side and the filament was rapidly cooled to 4000°C.
We proposed a method for producing polyamide multifilament characterized by drawing at a speed of m/min or higher.

Furthermore, the present inventors proposed in Japanese Patent Application No. 63-140506 a polyamide multifilament with an irregular cross section that can exhibit natural crimp based on the same principle as the polyamide multifilament proposed in Japanese Patent Application No. 140505/1982. . This is also manufactured by the manufacturing method disclosed in Japanese Patent Application No. 140504/1983.

Patent Application No. 63-140505 and No. 63-14oso
The latent crimpable polyamide multifilament described in No. e develops coil-like crimp when heat treated under no tension. The coiled crimped yarn shown in these two prior applications can have a wide range of crimp elongation rates, which is an important characteristic of crimped yarn.

In other words, it can have a crimp elongation rate equivalent to that of commercially available mechanically processed carpet crimped yarns. However, this coiled crimped yarn has the disadvantage that the spring constant of the crimp is small.

This means that the deformation rate under small tensile or compressive loads is large, which is a major weakness when used in carpets.

The present invention is disclosed in Japanese Patent Application Nos. 63-140505 and 63-1.
Instead of coiled crimping from the latent crimped polyamide multifilament proposed in No. 40506, the crimped polyamide multifilaments are three-dimensionally random, i.e., the direction of the crimps is indeterminate, similar to machined polyamide crimped yarns (e.g. BCF carpet yarns). A polyamide crimped yarn that develops regular crimps and whose spring constant, crimp elongation rate, and crimped elastic recovery rate are similar to or similar to machined polyamide crimped yarns for carpets is processed through a complicated process. The aim is to provide it at a low price without having to go through the process.

The spring constant, crimp elongation and crimp elastic modulus of commercially available polyamide crimped yarn (BCF carpet yarn) range from 0.6 to 1.0.15 to 35% and from 80 to 95%, respectively.

[Means to solve the problem]

As a result of intensive research on the method of manifesting crimp in latent crimpable polyamide multifilament obtained by high-speed spinning, the present inventors found that crimped yarn with a relatively high crimp elongation rate by heat treatment under no tension. We have discovered that by heat-treating a latent crimpable polyamide multifilament under load, the spring constant of the crimped yarn tends to increase, and we have arrived at the present invention.

That is, the object of the present invention is to produce a crimped yarn that has a degree of crystal orientation measured by wide-angle X-ray diffraction of 80% or more and exhibits a crimp elongation rate of 50% or more by hot water treatment at 98°C for 5 minutes. This is achieved by heat treating the resulting latent crimpable polyamide multifilament under a tension of 1 to 10111 g/d.

In the present invention, the degree of crystal orientation measured by wide-angle X-ray diffraction must be 80% or more; if it is less than 80%, the average orientation of the multifilament will be insufficient and the strength will be less than Ig/d, making it impractical for practical use. A preferable range of the degree of crystal orientation, which is unbearably small, is 85% or more, and a more preferable range is 90% or more.

When the polyamide multifilament single yarn in the present invention has a circular cross section, the birefringence of each single yarn has a radial distribution, and the distribution is asymmetrical with respect to the central axis of the single yarn. It is a requirement for expression. A single yarn that meets this requirement has a distribution of heat shrinkage behavior in the radial direction, and the fact that this distribution is eccentric is the principle behind the appearance of natural crimp due to heat treatment.

The birefringence distribution and asymmetry are observed and measured by interference fringes using a transmission interference microscope. The birefringence distribution is observed as being deviated from the U-shaped or V-shaped interference fringes shown in FIGS. 2(a) and 2(b) by the method described later.

Even when the single yarn has an irregular cross section, the principle of natural crimp development is exactly the same as when the yarn has a circular cross section. However, in the case of an irregular cross section, it is impossible to measure the birefringence using a transmission interference microscope, so the birefringence distribution cannot be cited as a requirement.

In the polyamide crimped yarn of the present invention, any polyamide may be used as long as it is fiber-forming, but nylon 66, nylon 6, nylon 12, nylon 46, etc. are preferable from the viewpoint of cost. Further, the polyamide may be a mixture of multiple polyamides, or may be a copolymerized polyamide, and these polyamides may be manufactured by known manufacturing methods, and may include additives such as antistatic agents, matting agents, and flame retardants. may be included.

Further, the cross-section of the polyamide crimped yarn may be either circular or irregularly shaped, but irregularly shaped is preferable for carpets.

The latent crimpable polyamide multifilament obtained by the production method of the present invention must exhibit a crimp elongation rate of 50% or more when treated with hot water at 98° C. for 5 minutes. If this is less than 50%, no matter what heat treatment is performed, it will not be possible to achieve the same relationship between the spring constant, crimp elongation, and crimp elasticity as BCF carpet yarn; if it is more than 50%, the tension in the heat treatment will By appropriately selecting the temperature and temperature, the object of the present invention can be achieved.

In the present invention, latent crimpability requires that the polyamide multifilament be heat-treated at a temperature of 150° C. or higher under a tension of 1 to Lomg/d.

Without heat treatment, latent crimp cannot be brought out.

If the tension during heat treatment is less than 1 mg/d, coil-like crimp will occur no matter what temperature is chosen, and the spring constant will be 0.05.
1111? / d/ mm and the object of the present invention cannot be achieved, and the tension during heat treatment is less than 110 n1/ mm.
d or more, no matter what latent crimpable polyamide multifilament and heat treatment temperature are selected, practical crimp cannot be manifested.

If the heat treatment temperature is less than 150°C, no matter what kind of latent crimpable polyamide multifilament and tension during heat treatment are selected, coil-like crimp occurs or practical crimp cannot be realized. preferred crimp elongation rate,
The tension and temperature during heat treatment are 65% to 85%, respectively.
4 to 8 mg/d and 180 to 220°C.

The latent crimpable polyamide multifilament of the present invention can be produced using the apparatus shown in Fig.
According to the method proposed in No. 04, it can be obtained by appropriately selecting the take-up speed, the application position of the aqueous liquid (the temperature of the filament), etc.

The heat treatment in the present invention can be carried out in a laboratory by hanging a predetermined load on the polyamide multifilament in an oven set at a predetermined temperature. Tension is adjusted by changing the load. When the heat treatment in the present invention is carried out industrially, it can be carried out continuously using an apparatus as shown in FIG. 6 is a feed roll, 7 is a take-up roll, 8 is a heater, 9 is a latent polyamide multifilament, 10
is a polyamide crimped yarn. The heater can be contact type or non-contact type (
The heat source may be hot air, steam, electric heat, etc. The tension is adjusted by the temperature of the heater and the speed ratio of the feed roll and take-up roll.

Further, the present invention can also be carried out using an apparatus in which the spinning process and the heat treatment process are continuous, as shown in FIG.

〔Example〕

The present invention will be explained in detail with reference to Examples. The method for measuring the properties of the polyamide multifilament of the present invention will be described below.

(a) Single yarn temperature The single yarn temperature was measured in a non-contact manner along the spinning line using a scanning infrared thermometer.

(b) Crystal orientation degree The crystal orientation degree of polyamide multifilament can be measured using the Xlt! manufactured by Rigaku Denki Co., Ltd. Generator (RU-200PL),
Fiber sample measuring device (FS-3), goniometer (SG)
-9), a scintillation counter is used as the counter, and a liquid height analyzer is used as the counting part, and the measurement is carried out using a CuK line (λ = 1.5418) made monochromatic with a nickel filter. The X-ray generator operates at 30kV and 80III^.

The goniometer is set to the 2θ value of the diffraction peak obtained from the equatorial diffraction curve. Using the symmetrical transmission method, the azimuthal direction is scanned from -30° to +30° and the diffraction intensity in the azimuthal direction is recorded. Furthermore, the diffraction intensity in the azimuth directions of -180° and +180° is recorded. At this time, the scanning speed was 4°/min, the chart speed was 10 mm/min, the time constant was 1 second, the collimator was 2 mmφ, and the receiving slit had a vertical width of 1.9 mm and a horizontal width of 3.5 am.

To determine the degree of crystal orientation from the obtained diffraction intensity curve in the azimuthal direction, the average value of the diffraction intensities obtained at +180° is taken, and a horizontal line is drawn to use it as a base line. Draw a perpendicular line from the top of the peak to the baseline and find the midpoint of its height. A horizontal line passing through the midpoint is drawn, and the distance between the intersection of this horizontal line and the diffraction diffraction curve is measured, and this value is converted into an angle (°), and the value is defined as the orientation angle H. The degree of crystal orientation is given by the following formula.

(c) Crimping elongation rate and crimp elasticity polyamide multifilament was made into a small winder with 20 turns using a measuring machine with a frame circumference of 1.125 m. After heat-treating the obtained small cold with boiling water at 98°C for 5 minutes under no load, it was heated to constant temperature (temperature 20 ± 2°C, relative temperature 65°C) day and night.
±2%) in a room.

A load of 2 mg/d was applied to the humidity-conditioned fibers for 1 minute, and the wind length was 1. 0 Next, apply a load of 0.1 g/d to the small wind, measure the wind length 12 after 1 minute, immediately remove the load, then apply a load of 2+ng/d to the small wind, and after 1 minute, measure the wind length. Measure the length r. The crimp elongation rate and crimp elasticity are expressed by the following equations.

12-1° Crimp elongation rate = x 100 (%) In consideration of sample variations, measurements were taken at 10 points for each sample and the average value is shown.

(d) Observation of interference fringes using a transmission interference microscope Using a transmission quantitative interference microscope manufactured by Carl Zeiss Jena, East Germany, observe interference fringes with an electric field vector parallel to the fiber axis using green light (wavelength 549 μm). . If the interference fringes are symmetrical or asymmetrical with respect to the central axis of the fiber, or if the lowest point or the highest point of the U-shape is not on the central axis of the fiber, it is determined to be asymmetrical.

(E) Strong elongation TENSILON UTM-I manufactured by Toyo Baldwin Co., Ltd.
Measurement was carried out using an I-20 type tensile tester at a support of 20c+a and a tensile speed of 20 cm/min.

(to) average refractive index < nt ・n), average birefringence (
Δn)> Define by the interference fringe method using a transmission quantitative interference microscope (interference microscope Interfaco manufactured by Carl Zeiss Jena). Using green light with wavelength λ = 549 mμ, 0.2
The fiber is immersed in a mounting medium that has a refractive index (N>) that gives a shift of the interference fringes in the range of ~2 wavelengths and is inert to the fiber, and the fiber axis is aligned with the optical axis of the interference microscope and the interference fringes. The interference fringe pattern created when the pattern is perpendicular to the opposite direction is photographed and analyzed after being enlarged approximately 1500 times.Figures 2 and 5
The figure shows an example of a pattern diagram of one interference fringe of a fiber. For example, when analyzing the pattern shown in Figure 5, the refractive index between points s' and s'' on the outer periphery of the fiber is expressed as (or n/), (where n□ or n/ is relative to the fiber axis, respectively). ), the thickness of s'-s'' is t, the wavelength of the light beam used is λ, and the distance between parallel interference fringes in the background is D.
, where d is the deviation of interference fringes due to fibers, and N is the refractive index of the mounting medium, the optical path difference is expressed as L--λ-(n,-N)t or (n,-N)L, as follows.

Let the radius of the fiber be R, and the center R0 of the fiber and the point R1 on the outer periphery
By measuring the deviation d of the interference fringes at each position between the two, n (or above n) at each position can be determined from the above equation, and the refractive index distribution in the radial direction of the fiber can be determined.

The distance from the bottom of all the fibers to each position is r, and x-r/
Let R=O1, that is, the refractive index at the center of the fiber, be the average refractive index n/(0) (or nl(.,)).

X is 1 on the outer circumference (r=R) and 0 on other parts
Although it takes a value between ~1, for example, the refractive index at the position x-0,8 is n/. ,,) or on n. ,6. Expressed as

Also the average refractive index nt torh mouth. , the average birefringence (Δn) is as follows.

Δn=n〆(0) on n(01 Also, the local birefringence Δn(
r> is represented by the following formula.

Δn (rl= n/ (rl nJL (r)(
g) Spring constant latent crimpable polyamide multifilament or polyamide crimped yarn that has already developed crimp is treated with hot water at 98° C. for 5 minutes. Then air dry for about - day and night. Thereafter, a crimped yarn having a length of 1 m is sampled when a load of 1111 g/d is applied.

The load applied to this sample was gradually increased, and the elongation of the sample at that time was measured, and the loads V and S were measured.

The relationship between elongation is illustrated. Calculate using the following equation from the slope of the initial straight line part of the obtained diagram.

X: Initial straight line elongation (ma+) y: Load applied to obtain the initial straight line elongation (+sg) 66 multifilaments were manufactured. The manufacturing conditions at that time were as follows.

Polymer relative viscosity η, 2.62 (95% I1.SO,
.

I Fi / 100cc) Spinneret (discharge hole is circular cross section) Hole diameter: 0.3m, number of holes: 4 Extrusion temperature (spinning temperature): 300℃ Aqueous liquid Water at room temperature Winding speed: 7000m/min Single yarn denier becomes 14 denier Set the polymer discharge amount to
The nylon 66 multifilament was wound up while applying an aqueous liquid from one side of the filament at a position where the temperature was 2°C.

Table 1 shows the physical properties of the latent crimpable polyamide multifilament wound up.

Table Note: δΔn:Δn 401)-Δn(0) Under the heat treatment conditions for crimp elongation measurement (98° C., 5 minutes, no-load hot water treatment), both ll&ll and N12 developed coil-shaped crimp.

The above 1lhl, 1lh2 latent crimp nylon 66
The multifilament was heat-treated in an oven at 200°C for 10 seconds with varying loads.

Table 2 shows the crimp situation that occurred at that time.

For those with irregular crimp forms, the crimp elongation rate, crimp elastic recovery rate, and spring constant are B.
Those values range for CF carpet yarns, 15
~35%, 80~95%, 0.6~1.0+ag/d/
-It's within range of the plow.

Second Table Note Irregular: The crimp direction is irregular (three-dimensionally random) Daiyu Zheng 1 The nylon 66 multifilament of Seed 1 in Example 1 was fixed at a load of 0.6 mg/d, and the temperature Heat treatment was carried out in the same manner as in Example 1, with different values.

The circumstances of the appearance of crimp are as follows.

〔Effect of the invention〕

As mentioned above, the method for producing polyamide crimped yarn of the present invention is an extremely simple method based on a high-speed spinning method, so that the crimped yarn for carpets can be provided at an extremely low cost, and the crimped yarn obtained can be has the same crimp elongation rate and spring constant as commercially available machine-processed carpet crimped yarns, and therefore, carpet crimped yarns with excellent quality and price can be obtained by the production method of the present invention.

[Brief explanation of the drawing]

FIG. 1 shows a specific example of a latent crimp polyamide multifilament manufacturing apparatus according to the present invention. 1... Spin head, 2... Spinneret, 3...
filament, 4... aqueous liquid supply roll, 5...
Winding section. Figure 2 shows an example of filament interference fringes observed with a transmission type interference closed microscope, and Figure 2 (a) shows an example of fibers asymmetric with respect to the central axis of the fiber obtained by the present invention. b) is an example of symmetry with respect to the central axis of the fiber. FIG. 3 is a diagram showing an example of an apparatus for continuously performing heat treatment according to the present invention. 6...Feed roll, 7...Take-up roll, 8.
...heater, 9...latent crimpable polyamide multifilament, 1
0...Polyamide crimped yarn. FIG. 4 is a diagram showing an example of an apparatus for carrying out the heat treatment of the present invention continuously with the manufacturing process of latent crimpable polyamide multifilament. 11... Spin head, 12... Spinneret, 13.
... Filament, 14... Aqueous liquid supply roll, 15... Spinning side take-up roll and heat treatment side feed roll 16... Heat treatment side take-up roll, 17... Heater, 18... Winding Department. FIG. 5 is an example of an interference fringe pattern used for measuring the cross-sectional radial birefringence distribution of the fiber (nt or n). In the figure, (a) is a cross-sectional view of a fiber, and (b) is an interference fringe pattern diagram, in which 19 is a fiber, 20 is an interference fringe due to the mounting medium, and 21 is an interference fringe due to the fiber. Figure Country Figure Figure (a) (b) Funeral diagram procedure amendment (method) % formula % Indication of the case 1985 Patent Application No. 2746 ■ No. 1 2゜ Name of the invention Method for manufacturing polyamide crimped yarn 3゜Relationship with the case of the person making the amendment

Claims (1)

[Claims] Latent crimps that have a degree of crystal orientation measured by wide-angle X-ray diffraction of 80% or more and can become crimped yarns that exhibit a crimp elongation rate of 50% or more by hot water treatment at 98°C for 5 minutes. 1. A method for producing a polyamide crimped yarn, which comprises heat-treating polyamide multifilament at a temperature of 150° C. or higher under a tension of 1 to 10 mg/d.