JPS62149934A - Production of thermoplastic synthetic fiber - 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 Field of Industrial Application The present invention relates to a method for producing a thermoplastic composite [1]. More specifically, m made of thermoplastic synthetic polymer
The present invention relates to a method for producing fibers with high strength and excellent workability by drawing s to a high magnification at high temperatures or heat-treating the fibers.

Conventional technology In recent years, the requirements for synthetic fibers have become more sophisticated, especially high strength,
In response to the demand for high modulus, various new fiber materials have been developed. Among them, for example, aromatic polyamide fibers, in particular fibers of substantially para-oriented aromatic copolyamides containing ether linkages in some of the polyamide repeating units, as described in British Patent No. 1,501,948. If so, in order to achieve its performance, the undrawn yarn is
A method is adopted in which the film is stretched at a high temperature of 00° C. or higher to a total stretching ratio of 6 times or more.

In addition, high-molecular-weight polyethylene fibers are stretched to a very high magnification at high temperatures near their softening point to produce high-strength LLI fibers, and fully aromatic polyester 11 miscellaneous is heat-treated at high temperatures for long periods of time to improve fiber properties. This is also being done.

However, when stretched or heat treated at such high temperatures,
The yarn becomes significantly softened and a phenomenon of fusion between the single 1iIlff occurs. In particular, as the number of filaments in the yarn increases, the fusion increases more and more, which not only reduces the spinning properties but also makes the obtained IIi fibers extremely inflexible.

In order to solve this problem, a method has been proposed in which fine inorganic powder is applied to aromatic polyamide fibers prior to drawing or heat treatment to prevent fusion and improve spinnability (US Pat. No. 4,525,384).

However, this method has the disadvantage that the inorganic fine powder applied to the fibers remains even after stretching, which has an unfavorable effect on the processability of the resulting fibers. For example, there are drawbacks such as a decrease in adhesion to the matrix and a decrease in fiber cohesiveness.

As mentioned above, the main purpose of the present invention is to improve spinning properties by preventing the fusion between single fibers that occurs when fibers are drawn or heat treated at high temperatures, and to improve fiber cohesiveness and processability. The aim is to improve the quality of fibers and produce high quality fibers.

DESCRIPTION OF THE INVENTION According to the present invention, the above-mentioned object is to coat a thermoplastic synthetic polymer fiber with an inert inorganic fine powder, and then draw the IIN at a high temperature to a high magnification or heat-treat it to produce a high-strength fiber. In this method, after stretching or heat treatment, the inorganic fine powder adhering to II is removed by water application treatment and air jet treatment to obtain a! having excellent workability. This is achieved by manufacturing fibers.

The term "fiber made of a thermoplastic synthetic polymer" as used in the present invention generally refers to undrawn yarns, two-part drawn yarns, or drawn yarns of thermoplastic synthetic IIi miscellaneous that can be heat-stretched or heat-treated.

Such thermoplastic synthetic fibers can include various types of synthetic 1Ii1a that are stretched or heat-treated at high temperatures and high magnifications that cause fusion between single fibers, but representative examples include: Examples include aromatic polyamide lIm, polyethylene fibers having an average molecular weight of 100,000 or more, which are stretched at high temperatures, and fully aromatic polyester rats, which are heat treated at high temperatures.

Aromatic polyamide fibers suitable for the present invention include:
80 mol% or more (preferably 90 mol% or more) of the repeating units constituting the polyamide are -NH-Ar + -NH
1iilt consisting of an aromatic homopolyamide or an aromatic copolyamide which is CO-Δr2-CO- is mentioned.

[Ar+, Ar7 are, Shows the same or different aromatic residues selected from

However, the hydrogen atom of the aromatic residue may be substituted with a halogen atom and/or a lower alkyl group. ] Regarding the manufacturing method of such aromatic polyamide, for example, British Patent No. 1501948, U.S. Patent No. 3
It is described in specification No. 733964, Japanese Unexamined Patent Publication No. 100322/1984, etc.

In the method of the present invention, among the aromatic polyamides, Ar 1. 80 mol% or more of Ar2 is the following aromatic residues (A), (B), (B') [the hydrogen atoms of these aromatic residues are substituted with a halogen atom and/or a lower alkyl group] It's okay. ] and the total mole % of the structural units (B) and/or (B') is 10 to 40%. Particularly preferred are aromatic copolyamides.

Examples of such aromatic copolyamides include copolyamides composed of one unit of the following three monomers.

The above-mentioned aromatic polyamide fibers, especially fibers made of aromatic copolyamides containing ether bonds in a part of the polymer, are prepared by drawing undrawn yarns to a high ratio to obtain drawn yarns with high strength and high modulus. It is necessary to perform "flow stretching" in which the undrawn yarn is heated to a temperature of 300° C. or higher, preferably 350 to 550° C., and gradually stretched to avoid necking. For this reason, it is necessary to lengthen the zone in which the yarn is heated to a high temperature so that the heating time until the end of stretching is 0.2 seconds or more.

At this time, it has been found that since the yarn is drawn at a high temperature, the single fibers soften and fuse with each other, resulting in poor drawability and deterioration in the quality of the drawn yarn. It has also been found that when this type of fiber is stretched on a hot plate used for stretching, the yarns are compressed as an aggregate to the hot plate, which further increases fusion.

The same phenomenon occurs when producing high-strength polyethylene m*. For example, polyethylene with a weight average molecular weight of 1,000,000 is dissolved in decalin to make a 2% solution, this solution is spun from a spinneret with multiple holes, introduced into cold water and coagulated, the solvent is extracted, and then dried at 120°C. If the film is stretched approximately 40 times in the above manner, a high tensile strength l1m with a Young's modulus of 50 GPa or more can be obtained. However, the single fibers of the dried fibers are stuck to each other before being stretched, and if they are stretched at 120° C. or higher, they will partially fuse and lose their flexibility as multifilaments.

Furthermore, after melt-spinning the wholly aromatic polyester,
1 inch is heat treated at high temperature to create high strength and high modulus mH.
There is also the problem that fusion between tivs occurs during heat treatment.

For example, JP-A-50-43223, JP-A-50=
157619 discloses 1Iit4 made of various wholly aromatic polyesters. These wholly aromatic polyesters have high strength and a high Young's modulus of 1! If you try to melt-spun this into a high-polymerized polyester that has a high molecular weight, it will have poor spinnability, so it will be spun in a relatively low-molecular-weight state, and after spinning, it will be heat-treated at high temperatures for a long time to increase the molecular weight as desired. It is necessary to set the physical properties of the van. Since such heat treatment is carried out at high temperatures for a long period of time, fusion between fibers cannot be avoided if heat treatment is carried out by a normal method.

In the method of the present invention, in the drawing or heat treatment of thermoplastic synthetic fibers that tend to fuse together single fibers during such drawing or heat treatment, an inert inorganic fine powder is first applied to the fibers to uniformly coat the surface of the 4illiH. A coating of fine inorganic powder is formed and the raett is then stretched or heat treated at high temperature and high magnification.

By applying such an inorganic fine powder, it is possible to significantly reduce the phenomenon of fusion between single fibers, which could not be avoided in the past, and it is possible to improve the fusion to a state where it is almost completely eliminated. .

The inert inorganic fine powder used in the method of the present invention is an inorganic fine particle that is chemically stable even at high temperatures during drawing or heat treatment and does not exert any chemical action (for example, oxidation, etc.) on the yarn. Regarding the size of the inorganic fine powder, the smaller the particles, the better, and the average particle size is 20 microns or less, particularly 10 microns or less, which is preferable because it will adhere uniformly to the surface of the aiN.

There are many inorganic fine powders that can be effectively used in the method of the present invention, and among them, aluminum silicate.

Particularly preferred are one or more inorganic substances selected from magnesium silicate, graphite, talc, silica, and mica.

These fine powders may be used as a single component or in combination of two or more. Further, these fine powders and powders may be hydrated in an aqueous dispersion bath to form a colloid, or simply dispersed, and both can be used.

[The method of applying these fine powders to T is to prepare a dispersion bath in which fine powders are dispersed in a dispersion medium such as water,
It is preferable to dry the material after immersing it in the dispersion bath.

In addition, in order to uniformly disperse the inorganic fine powder, an organic or inorganic dispersion aid may be added to the dispersion bath, or an antistatic agent or a thickener may be used in combination to improve the cohesiveness of the threads. I don't mind.

The adhesion amount of inorganic fine powder to 1IiN is 0.5 to 3%.
is appropriate. 1.0 to 2 to obtain good stretchability
．． 0% by weight is preferred.

On the other hand, when focusing on fibers obtained by drawing or heat-treating by the above method, most of the inorganic fine powder adhering to the fibers remains, and the larger the remaining amount, the more adversely the processability is affected. Therefore, it is necessary to remove the inorganic fine powder adhering to the fibers, but during drawing or heat treatment, the fibers may be heated to high temperatures and become semi-molten, causing the inorganic 'm'# on the fiber surface to disappear.
The iI terminal is not easily overlooked.

For this purpose, in the method of the present invention, water is first applied to the drawn yarn or the heat treatment system. Specific means of water application treatment include:
For VA navy blue, it is preferable to immerse it in water (including running it underwater) or to spray it with a water shower. However, this water application treatment alone does not remove the adhering inorganic fine powder to the extent that the fiber surface is liberated.

Therefore, in the method of the present invention, it is important to further inject an air stream into the water-applied surface to blow off the inorganic fine powder liberated by the water-applying treatment together with the water. This effectively reduces the amount of inorganic fine powder remaining in the m-fibers. If this residual amount is less than 1.0% by weight, there will be no practical problem in processability.

In addition, the effect of this water application treatment and air jet treatment is not only to simply remove inorganic fine powder, but also to moisten the fibers, which makes it easier to apply finishing oil uniformly. The cohesiveness of the fabric is significantly improved, and weavability is further improved. ' As a specific means for the above-mentioned air jet treatment, a method of directly spraying the air flow onto the running yarn may be used, but the running yarn may be sprayed with a diameter of 1 to 3 rt, which is generally called an air nozzle.
It is practically advantageous to introduce the air into a tubular part with a length of 0.5 to 3 cm and inject air from the wall surface inside the pipe.

The water application and air jetting treatments may be performed in a separate process after the mlIC is once rolled up, or may be performed continuously in the process immediately after stretching. Further, if the water application treatment and the air jet treatment are performed in two stages or repeatedly, the effect of removing inorganic fine powder is further enhanced.

Effects of the Invention According to the method of the present invention, first, an inert inorganic fine powder is applied to the fiber, and the surface of the single fiber is thinly coated with the inorganic fine powder.
In addition to suppressing the occurrence of fusion between single fibers, by applying both water application treatment and air jet treatment in this order to the fibers that have been drawn or heat treated at high temperatures and high magnification, it is possible to prevent the occurrence of fusion between single fiber strands. It is possible to obtain a high-quality IJi cloth with almost no fusion, high strength, high modulus, excellent convergence, good U properties, no problems such as scum generation, and excellent adhesion. .

The resulting fibers can be used in a wide variety of applications, including woven fabrics and reinforcing materials for rubber and resin.

EXAMPLES Hereinafter, the method of the present invention will be explained in more detail by way of examples. Note that the main characteristic values used in the following examples are values measured as follows.

(1) Intrinsic viscosity of the polymer (I\/) Using an Ostwald type viscosity tube, the flow time of only the solvent is to (seconds), the flow time of the dilute solution of the polymer is t (seconds), and the flow time of the dilute solution of the polymer is t (seconds). Let the polymer concentration be c(
g/dj), it is expressed as IV=In(t/lo)/c. Unless otherwise specified, the solvent is 91.5% sulfuric acid, c = 0.5 g/dj, and measurements are taken at 30°C.

(2) Degree of fusion: Total number of filaments of drawn or heat-treated yarn (N)
Among them, the number (n) of filaments that are not fused and can be separated one by one is counted, and the degree of fusion is determined using the following formula.

Degree of fusion = ((N-n)/2N) x 100 (%) This measurement is performed five times and the average value is taken.

(3) Amount of attached and remaining amount of fine inorganic powder The amount of attached and remaining amount of fine inorganic powder is measured as follows. Prepare lIN without applying finishing oil in advance,
Sample about 3g of this. Then, it was dried at 120°C for 1 hour and the weight was measured. Let this be A(g). This sample is completely incinerated in an incinerator at 800°C.

The ash weight after ashing is measured and calculated as B (g) using the following formula.

Adhesive amount (or residual amount) - (B/ (A-8)) x 100 (%) Example 1 An aromatic compound with IV = 3.1 composed of one unit of the following monomer, -CO + CO- 50 mol% Polyamide containing N-methyl chloride (CaCf2)
A 6% by weight polymer solution in 2-pyrrolidone (NMP) was extruded through a spinneret with a 3 mm pore size and 250 holes at a speed of 83 g/min. Approximately 0 in the air
After running for m, it was coagulated in a coagulation bath of NMP/water (30/70 wt%) at 50°C and pulled up at a speed of 117 rLZ min. Subsequently, the obtained coagulated thread was pre-stretched stepwise to 1.3 times while being washed in a water bath at 50°C, passed through a squeezing roller to remove water adhering to the surface, and the composition as shown in Table 1 was obtained. The yarn was immersed in a bath of an inorganic fine powder dispersion for about 5 seconds by passing it through a Nelson roller, and then passed through a squeezing roller to obtain a water-washed yarn (pre-drawn yarn) to which the inorganic fine powder liquid was attached. Subsequently, the washed yarn was passed through a set of a drying roller with a diameter of 20 cm and a separate roller with a diameter of 3 cm and a surface temperature of 120°C.
A drying roller with a diameter of 1.5 cm and a diameter of 1.5 c at 0 °C
10 turns and 5 turns for each set of m sepa and rate rollers.
The yarn is wrapped around a single string and dried to form a completely dry yarn, which is then stretched to a total stretching ratio of 11.0 times while contacting a hot plate with a surface temperature of 500°C and a length of 1 TrL. I rolled it up.

The obtained drawn yarn was unwound at a speed of 50 m/min, immersed in a washing bath with a length of 1 m, and then pulled up and an air stream was sprayed through an air nozzle to remove the inorganic fine powder. The air nozzle has an inner diameter of 1.5 gates and has a slit for introducing the running yarn. The inner wall of the air nozzle has 1. One omm air injection hole is provided.

When the running yarn passes through the air nozzle, the airflow collides with the running yarn, and the attached inorganic fine powder is blown off along with the water content. The air flow used was 100 ohms/'min. 2% finishing oil was applied to the drawn yarn treated in this way and 5
It was rolled up at 0 m/min.

For comparison, experiments were also conducted in cases where no inorganic fine powder was used and where all or part of the fine powder removal process of the present invention was omitted.

These results are shown in Table 1 below.

As shown in Table 1, when no inorganic fine powder is used (
In experiment No. 1), there was a lot of fiber fusion and the strength was low. When f=J is applied to the inorganic fine powder consisting of talc/osmos, the fusion becomes almost zero, but if no inorganic fine powder removal treatment is performed (Experiment No. 2), the convergence is poor. In Experiment No. 3), when water immersion treatment was performed, a considerable amount of inorganic fine powder was removed, but it was still not sufficient and the focusing property was not improved much.

When only air jet is performed using an air nozzle (Experiment No. 0.
4) has almost no effect.

When water immersion is followed by air jet injection as in the present invention (Experiment No. 5), the combination of the two effectively removes inorganic fine powder and significantly improves convergence.

Example 2 The same aromatic polyamide solution as in Example 1 was prepared with a pore size of 0.25.
It was extruded from a spinneret with 667 holes and extruded at a rate of 740 g/min, and after traveling 7 mm in air, the temperature was 50 mm.
It was coagulated in a coagulation bath of an NMP aqueous solution having a concentration of 30% by weight at 10°C and pulled at a speed of 38.5 m/min.

Subsequently, the 1q coagulated thread was washed in a water bath at 50°C and stretched stepwise to 163 times, passed through a squeezing roller to remove water adhering to the surface, and then stretched to 1 q.
The fibers were immersed in an aqueous dispersion bath containing ω% heavy inorganic fine powder for about 1 second and passed through a squeezing roller to obtain a water-washed yarn (pre-drawn yarn) to which the inorganic fine powder was attached.

Table 2 Next, this washed yarn was dried by winding it around a drying roller at 120°C 30 times, and then the dried yarn was rubbed between a pair of gear rolls with triangular teeth on the right side. , each gear roll has a diameter of 84 mm and 40 triangular teeth on the circumference, and the tips of the triangular teeth have a radius of curvature of 1 mm.
It is finished so that it has a rounded shape.

The gear rolls are engaged with each other to a certain depth, and the degree of kneading changes depending on the depth of this engagement.

The depth of engagement was 0.6 mm. This massaging makes it easier to open the fibers during stretching at 400° C. or higher and reduces fusion.

After kneading and loosening, the dried yarn was heated to 360°C.

Stretched twice on a hot plate with a length of 2 TrL, and finally at a temperature of 50
It was stretched 4 times on a hot plate having a length of 3 TrL at 0°C.

(Thus, the total stretching ratio is 10.4 times.) The thus obtained drawn yarn was continuously treated to remove inorganic fine powder by the method shown below without being wound up.

First, a water shower is sprayed onto the running drawn yarn. The water flow rate of the shower is 101/min. The drawn yarn is sufficiently wetted by this water shower. Then inner diameter 2.5M, length 1
Introduce into 0# air nozzle. The inner wall of the air nozzle has a diameter of 1.7 mm. There are 200 Jl/min of air injection holes through these pores, which collide with the running wet drawn yarn and blow off the inorganic fine powder adhering to the mat together with water.
. After this, the water shower and air jet treatment were repeated under the same conditions. The thus treated drawn yarn was coated with 1.8% finilazing oil and wound at a speed of 400 m/min. The fineness of the obtained fiber was 1030 denier.

For comparison, a drawn yarn without inorganic fine powder removal treatment was similarly oiled and wound.

A high-density fabric weaving test was conducted using these drawn yarns. The weave density was 32 threads per inch.

The above test results are shown in Table 3 below.

-Jo- As can be seen from Table 3, when the inorganic fine powder removal treatment was performed, the yarn quality was excellent and the weavability was also good. On the other hand, without inorganic powder treatment, the loom often stopped due to poor fiber cohesiveness, and scum was also observed on the guides.

Example 3 Polyethylene with a weight average molecular weight of 1 million was dissolved in decalin to make a 2% solution, and the solution was heated at 135°C from a 200-hole spinneret.
The fibers were spun at a spinning humidity of 5° C. and coagulated by introducing them into cold water at 5° C.

Decalin was extracted from this coagulated fiber in a methanol bath. According to the method of the present invention, the fibers were immersed in a dispersion bath of inorganic fine powder having the composition shown in Table 4 (talc concentration: 1.5%), and then squeezed with a squeezing roll and dried with a drying roll at 50°C. After stretching this dried Ili fiber 40 times on a hot plate at 140°C,
Fine talc powder was removed through a 1 m long water bath and then using the same air nozzle as in Example 1, and the finishing oil was 1.0%.
A high strength polyethylene tiam of 1000 denier/200 filament was obtained.

On the other hand, as a comparative experiment, it was dried without applying fine talc powder, stretched under the same conditions as above, and then 1.0% oil was applied and wound up.

Table 4 The results of these experiments are summarized in Table 5 below.

As shown in Table 5 above, the method of the present invention dramatically reduces fusion and significantly improves the cohesiveness of the final fibers.

Example 4 1350 parts of p-acetoxybenzoic acid, 31 parts of terephthalic acid
1 part of isophthalic acid, 104 parts of 4.4'-diacetoxydiphenyl, and 675 parts of 4.4'-diacetoxydiphenyl were charged into a reactor equipped with a stirrer and a distiller, and the mixture was heated at 250 to 330°C while distilling off the acetic acid produced by the reaction under a nitrogen gas stream. 3 hours, 330 more
The reaction was carried out at ℃ for 5 hours. After cooling, the produced polymer was pulverized to an absolute pressure of about 0.2 mm1- under reduced pressure of 230~2
Solid phase polymerization was carried out at 80°C for 3 hours and then at 280°C for 3 hours.

The wholly aromatic polyester obtained in this way has a diameter of 0.2
It was extruded at 360° C. through a circular nozzle with 12 holes, immersed in the same inorganic powder dispersion bath as in Example 2, dried, and wound up. The strength of this Il miscellaneous material is 6.5 g/de, Young's modulus is 4
The weight was 80g/de and the elongation was 1.3%.

The fibers were then heated at 200°C to 330°C in a nitrogen stream.
The humidity was raised over one hour, and then heat treatment was performed at 330° C. for 5 hours.

The fiber was passed through a 1771 length water bath and then passed through the same air nozzle as in Example 2 before being coated with finishing oil and wound up. This fiber has a strength of 24.7 g/de and a Young's modulus of 89.
It had an elongation of 0 g/da and an elongation of 2.7%, and was flexible with no fusion between single fibers.

On the other hand, for comparison, when yarn was spun in the same manner but no inorganic powder was applied and no water bath treatment or air nozzle treatment was performed, a yarn with a strength of 24.7 g/de was obtained, but the single fibers melted during the heat treatment. It was hard and rough when I wore it.

Claims (12)

[Claims] (1) In a method of producing high-strength fibers by applying inert inorganic fine powder to fibers made of thermoplastic synthetic polymers and stretching or heat-treating the fibers at high temperatures, after stretching or heat-treating, A method for producing thermoplastic synthetic fibers, which comprises subjecting the fibers to water application treatment and air jet treatment to remove the inorganic fine powder adhering to the fibers. (2) A patent in which the thermoplastic synthetic polymer is a rigid polymer consisting of aromatic residues or heterocyclic residues, and in which fusion occurs between single fibers when the fibers are stretched or heat treated at high temperatures. A manufacturing method according to claim (1). (3) The thermoplastic synthetic polymer contains 80 mol% or more of the repeating units of the polymer and the following repeating units: ■NH-Ar_1-NHCO-Ar_2-CO■ [Here, Ar_1 and Ar_2 are at least one selected from the following. Indicates a type of aromatic residue. ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas, chemical formulas,
There are tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ However, the hydrogen atom of the aromatic residue may be substituted with a halogen atom and/or a lower alkyl group. ] The method for producing an aromatic polyamide according to claim (1) or (2). (4) More than 80 mol% of Ar_1 and Ar_2 are the following aromatic residues (A) or (B), ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (B) [However, the hydrogen atoms of these aromatic residues may be substituted with a halogen atom and/or a lower alkyl group. ] The manufacturing method according to claim (3), wherein the mol% of said (B) is 10 to 40%. (5) 80 mol% or more of Ar_1, Ar_2 is the following aromatic residue (A) or (B'), ▲There are mathematical formulas, chemical formulas, tables, etc.▼(A) ▲Mathematical formulas, chemical formulas, tables, etc. Yes▼(B') [However, the hydrogen atoms of these aromatic residues may be substituted with halogen atoms and/or lower alkyl groups. ] The manufacturing method according to claim (3), wherein the mol% of said (B') is 10 to 40%. (6) Claims (1) or (2) in which the thermoplastic synthetic polymer is a homopolymer of wholly aromatic polyester, wholly aromatic polyether, or wholly aromatic polyketone, or a copolymer or mixture thereof. ) The manufacturing method described in section 2. (7) The manufacturing method according to claim (1), wherein the thermoplastic synthetic polymer is a polyolefin having a weight average molecular weight of 100,000 or more. (8) The manufacturing method according to claim (1), wherein the inorganic fine powder is a fine powder with an average particle size of 20 microns or less. (9) The inorganic fine powder is aluminum silicate, graphite,
Claim No. 1, which is a fine powder of at least one inorganic substance selected from the group consisting of talc, silica, and mica.
The manufacturing method described in item 1) or item (8). (10) The manufacturing method according to claim (1) or (9), wherein the water application treatment is performed by dipping and running the fibers in water. (11) The manufacturing method according to claim (1) or (9), wherein the water application treatment is performed by jetting water onto the running fibers. (12) The manufacturing method according to claim (1) or (9), wherein the air jet treatment is carried out by introducing running fibers into an air nozzle.