JPS60224809A - Polyamide fiber and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a polyamide fiber having excellent dimensional stability and heat resistance, by spinning a specific copolymerized polyamide in molten state, passing through the atmosphere in a heating cylinder thereby retarding the cooling of the yarn, and successively carrying out quenching, taking up, and drawing of the yarn. CONSTITUTION:A copolymerized polyamide composed of 98-85mol% tetramethylene adipamide unit and 2-15mol% other amide-forming unit and having a relative viscosity of >=3.0 (in sulfuric acid) is molten at a spinning temperature of 290-320 deg.C, and extruded through a spinneret. A heating cylinder having a length of 5-100cm and containing an atmosphere controlled at 200-400 deg.C is attached just below the spinneret to retard the cooling of the spun yarn. Thereafter, the yarn is quenched, taken up by a take-up roll, and drawn at a draw ratio of >=6.0 and >=90% of the critical draw ratio, to obtain the objective polyamide fiber having the characteristics shown in the table.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention provides a high strength, modulus,
The present invention relates to a polyamide fiber with excellent dimensional stability and heat resistance, and a method for producing the same.

(Prior art) Polyamide fibers, such as polypuffamide and polyhexamethylene adipamide fibers, have high strength, toughness, and durability, and have traditionally been used in various industrial applications such as tire cords, belts, and conveyance. It has been widely used for fishing belts, fishing nets, ropes, etc. However, the above-mentioned polyamide fibers have a low modulus and poor dimensional stability at high temperatures, so that their use is currently limited to bias tires, especially as tire cords.

Therefore, various modifications of polyamide fibers have been studied in the past for the purpose of imparting modulus and dimensional stability to the polyamide 1iAjI at a level applicable to radial tires, which are the mainstream tire structure.

Meanwhile, on the 4th floor, polytetramethylene adipamide was known as a new flat-crystalline material (for example, JP-A-56-14
9429, No. 56-149450, and No. 56-149431, if you take advantage of their characteristics,
Although it is expected that a high modulus, low contraction mJI will be obtained.

Polytetramethylene adipamide has a high melting point of 290°C or higher, and even if it is melt-spun as it is, it cannot be made into a stable yarn, so it has been said that it is difficult to obtain IIJI with high strength.

(Problems to be Solved by the Invention) The present inventors have aimed to develop a strong capolyamide fiber that retains the characteristics of polyamide fibers and has significantly improved modulus and dimensional stability. As a result of extensive research, we discovered that by spinning a copolyamide containing polytetramethylene adipamide polymer as the main component under specific conditions, we could obtain a new polyamide fiber that met the above objectives. The present invention was achieved by establishing the manufacturing conditions.

(Means for Solving the Problems) That is, the present invention provides tetofumethyleneazibamide units 98-
85 mol% and other amide-forming units 2-15 moA/
Copolymerized polyamide adipamide unit consisting of 96 to 98 to 8
5 mol % and 2 to 15 mol % of other amide-forming units.
A copolyamide consisting of a sulfuric acid relative viscosity of 5
0 or more copolymerizable polyamides are melted at a temperature of 290 to 520°C and spun through a spinneret.

(2) a length of 5 to 100 or directly below the spinneret;
A heating tube whose ambient temperature is controlled at 200 to 400°C is installed, and the spun yarn is passed through the heating tube atmosphere to delay cooling of the yarn.% (3) Yarn after passing through the high temperature atmosphere (4) After the yarn is taken off, it is drawn at a stretching ratio of 60 times or less and 90% or more of the limit stretching ratio. The present invention provides a method for producing a patented amide fiber characterized by the following.

(a) Strength T/D≧Bg/6 (mouth) Elongation 2620% e→ Initial modulus M1≧50g/eL ■ Boiling water shrinkage rate △8w≦5% (e)) Melting point Tm -275~288℃ Invention The copolyamide used in is 98 tetofumethyleneazibamide units.
~85 mol% and 2 to 15 mol% of other amide-forming units, with preferred copolymerization ranges of 95 to 90 mol% and 5 to 10 mol%, respectively. If the amount of tetofumethylene adipamide units exceeds 98 moA/96, the effect of the present invention due to copolymerization cannot be obtained, while if the amount is less than 85 mole percent, the crystallinity is markedly decreased, and polytetramethylene adipamide This is undesirable because the excellent characteristics of the polymer, such as modifiability and dimensional stability, which the polymer originally possesses, are lost.

Other amide-forming units that can be copolymerized with the tetramethylene azibamide unit include, for example, capramide. Hexamethylene adipamide, hexamethylene cepacamide, hexamethylene terephthalamide.

These include hexamethylene isophthamide, undecamethylene lentilephtamide, undecamide, metaphenylene isophthamide, buffed phenylene terephthamide, metaxylylene adipamide, etc. Among these, capfumide units are particularly used to produce copolymerized polymers. above and obtained 1j
Most preferred from the viewpoint of the characteristics of Aa.

The above copolyamide has a low melting point of 275°C to 288°C, and thermal decomposition foaming occurs at temperatures above 325°C, so its thermal stability is the same as that of the homopolymer. Therefore, by using the above copolyamide, , the spinnable temperature range is expanded, and lower spinning temperatures can be used.

The copolyamide used in the present invention is prepared by adding a 196 solution of 98% sulfuric acid at 25°C in order to obtain the desired flat strength m fibers.
It is necessary that the relative viscosity of sulfuric acid is 50 or more, preferably 55 or more, and the degree of polymerization is 55 or more.

Next, the method for producing the polyamide fiber of the present invention will be explained.

In method 2 of the present invention, first, the above-mentioned copolymer 29
After melting at a spinning temperature of 0 to 325°C and 295 to 320°C, it is filtered in a normal spinning pack and spun through a spinneret hole. Attach to a cylindrical heating cylinder of ~50I:11, introduce the yarn into the atmosphere of the heating cylinder heated to 4200 to 400°C, preferably 250 to 560°C, and delay cooling of the spun yarn. It is necessary.

Next, cold air is blown onto the yarn that has come out of the heating cylinder to rapidly cool it down. If the yarn spun from the nozzle hole is rapidly cooled directly under the first nozzle without passing through the atmosphere of the heating cylinder, the yarn cannot be spun stably, and the undrawn yarn taken off has a low strength/elongation product. Therefore, even if the female drawing is carried out continuously, it is not possible to draw at a high drawing ratio and a high strength yarn cannot be obtained, which is not preferable. When the lower limit of the ambient temperature is less than 5c11 and less than 200°C, respectively.

There is no sufficient thread heating effect (on the other hand, the upper limit is 100
A temperature exceeding 3 or 400° C. is not necessary in terms of the effect of heating the yarn, and is rather undesirable because it causes thermal oxidative deterioration of the spun yarn.

The appropriate condition for rapidly cooling the threads that have passed through the heating tube with cold air is to blow cold air at a temperature of 10 to 50° C. at a flow rate of 1 to 5 Nm'/min.

The cooled and solidified yarn is coated with an oil and then taken off by a take-up roll that rotates at a predetermined speed.

In this case, the take-up speed is 500 to 5000 m7 minutes II
It can be arbitrarily selected from the range IIX, and the discharge amount can also be set arbitrarily from 1 to 4 of SgZ.

Next, wind up the thread once with wine goo.

Alternatively, it is continuously subjected to the stretching process as it is.

For example, in the case of the direct spinning drawing method, the drawn yarn is spread to its orientation degree and the total drawing ratio is t+c #b −
-1+ n RR/l-1fii & ! m m 4,
n! x Jl + m y rh It is preferable to carry out the stretching at a stretching ratio of 90% or more of the critical stretching ratio, usually 92 to 96%, and to divide the stretching into multiple stages of two or more stages. Note that the critical stretching ratio here refers to It means the highest stretching ratio that allows stretching for at least 5 minutes or more.

After the yarn has been drawn, it is heat-set in a relaxed or tensioned state and then wound up with a winder.

Thus, the polyamide fibers obtained by the method of the present invention have excellent new properties as described above, but especially compared to conventional polyamide fibers such as polycabramide and polyhexamethylene adipamide fibers, they have a high melting point of about 15°C or more, Moreover, it is significantly different in that it exhibits a low boiling water shrinkage rate.

Furthermore, since the polyamide fiber of the present invention has a high melting point, there is little change in properties when heated to high temperatures.

For example, the shrinkage rate when exposed to 4-temperature air is small;
It exhibits excellent properties such as good retention of Mozief 15 strength at low temperature and small creep.

The polyamide fiber of the present invention has a weight of 8g/d or more, and a normal weight of 9a/d.
The copolyamide of the present invention has high crystallinity (and therefore has low heat fixability). Because of its excellent properties, it is possible to obtain fibers with high strength, high modulus, and low elongation by heat setting, with molecular chains in a highly oriented state during stretching.

The above characteristics of the polyamide fiber of the present invention are based on the following definitions and measurement methods.

k) Strength T/D (b) Elongation E (c) Initial modulus (synonymous with initial tensile resistance) Mi
: , R Engineering 8 According to the method of L-1017. 2 samples
After being left in a temperature and humidity controlled room at 0°C and 65% RH for more than 24 hours, it was measured using an 11 Tensilon UTM-4L tensile tester (manufactured by Toyo Baldwin Co., Ltd.) at a length of 251 and a tensile rate of 30c11/min. , the load-elongation rate curve was determined.

From this load-elongation rate curve? /D, K, Ml to J engineering 5
Based on the definition of L-1017.

) Boiling water shrinkage rate △SW: Take the sample in a skein shape,
After leaving the sample in a temperature and humidity controlled room at 0°C and 6596RH for 24 hours or more, a load corresponding to α1g/d of the sample was applied and the measured length was 1. The sample was placed in boiling water without tension.

After processing for 50 minutes, the yarn was air-dried for 4 hours in the temperature and humidity control room, and the yarn length lI was calculated using the following formula from the measured yarn length lI by applying the load again.

△SW-(go-Is)/A'ox+Do(%
Melting point Tm: The peak temperature of the melting curve is Tm ('C ).

Next, the present invention will be explained in detail with reference to the following examples.

Example 1 A polyamide (nylon 4°6/6) containing tetofumethyleneazibamide as a main component and capfumide as a copolymerization component at the ratios shown in Table 1 was added with iodide as a heat stabilizer. Copper (containing 3% by weight of LO and 11% by weight of potassium iodide) was subjected to the following melt spinning.

o, 4 with an extruder type spinning machine with a diameter of 30111φ
B! Use a hole ff113 φ, number of holes 54,
The spinning temperature (polymer temperature) was varied according to the copolymerization composition of the polymer as shown in Table 1. A heating cylinder with an inner diameter of 20 mm and a length of 50 α was attached directly below the nozzle, and the outermost yarn was placed 25 cm from the top of the heating cylinder. The atmospheric temperature at a position 11 away from the strip was 350°C. After passing through the heating cylinder, the spun yarn was cooled by blowing cold air at 20° C. over a distance of 1 m below the heating cylinder. Wind speed is 30m/min.
The flow rate was approximately SNm'. The cooled and solidified yarn was coated with a lubricant using an oil supply roll, then taken up by a take-up roll at 60°C rotating at a surface speed of 400 tn/min, then continuously stretched in two stages, and then wound up.

The stretching roll temperature was 200° C. for the first stretching row Iv.

--・nt(IdhMd+H95nτ-Yamaban-h[Marinyoro A/: Not heated, and the stretching ratio in the second stage was 4.0 times.

After the remainder was stretched in the second stage, 596 was relaxed and rolled up. The total stretching ratio was 95% of the limit stretching ratio. The obtained drawn yarn was doubled to have a denier of 1260, and the results of evaluation of its physical properties are also shown in Table 1.

As is clear from Table 1, the ma (mu 2 to 4) obtained from the copolymer of the present invention is stronger and has a higher modulus than that of the homopolymer (1) and the polymer with a high copolymerization ratio of other components (5). and dimensional stability are balanced and excellent.

Example 2 The copolymerized polyamide of Testom 3 shown in Example 1 (95 mol % of tetramethylene adipamide units/5 mol % of cadefamide units/l'*) was used, and the spinning conditions were varied as shown in Table 2. Spinning and drawing was carried out with a change. The properties of the obtained drawn yarn are also shown in Table 2.

As is clear from Table 2, if the spinning conditions are outside the range specified in the present invention (clamps 8 to 13), it is not possible to obtain polyamide fibers with balanced properties.

(Effects of the Invention) As explained above, the novel polyamide fiber of the present invention has excellent balance of strength, modulus, dimensional stability, and heat resistance, and is particularly suitable for use in rubber reinforcing materials such as tire cords and belts, and other materials. Useful as an industrial material.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Claims] 1. 98 to 85 mol% of tetofumethyleneazibamide units
A copolyamide fiber comprising 2 to 15 mol % of other amide-forming units and other amide-forming units, characterized in that it simultaneously has the following properties. (a) Strength T/D≧8g/d (b) Intensity 1 degree E≦2096 (c) Initial modulus M1≧30g/(to 1) Boiling water shrinkage rate △S
w≦5% -) Melting point Tm -275~288°C 2, (1) Tetofumethyleneazibamide units 98~85
Mol% and other amide-forming units 2-15 moA/96
A copolyamide consisting of a sulfuric acid relative viscosity of A
A copolymerized polyamide of O or more is melted at a temperature of 290 to 320°C and spun through a spinneret. (2) A heating cylinder with a length of 5 to 100 scratches and a controlled atmosphere temperature of 200 to 400°C is attached directly below the spinneret, and the spun yarn is passed through the heating cylinder atmosphere to cool the yarn. to delay. (3) rapidly cooling the yarn after passing through the high-temperature atmosphere;
In addition, a patent characterized in that the steps consisting of stretching at a stretching ratio of 90% or more of the limit stretching ratio are sequentially carried out (
a) Strength T/D≧a B7α (b) Elongation E≦20% (c) Initial modulus M1250g/d (d) Boiling water shrinkage rate △8w≦596 (e)) Melting point Tm-2
7 5, 2 8 8℃