JP2020094321A - Polyamide fiber and polyamide nonwoven fabric - Google Patents

Abstract

To provide a polyamide fiber and a nonwoven fabric having excellent mechanical properties and elastic modulus, small shrinkage, light weight, and excellent yarn-making properties.SOLUTION: A polyamide fiber or a polyamide nonwoven fabric comprises a resin composition containing 100 parts by mass of a polyamide and 0.1 to 10 parts by mass of a cellulose fiber having an average fiber diameter of not more than 10 μm. In the polyamide fiber or polyamide nonwoven fabric, the relative viscosity of the polyamide is 2.0 or more. In the polyamide fiber, the orientation degree of the cellulose fiber is 80% or more.SELECTED DRAWING: None

Description

The present invention relates to a polyamide fiber and a polyamide nonwoven fabric made of a resin composition containing a polyamide and a cellulose fiber.

Polyamide fibers and polyamide nonwoven fabrics are widely used as industrial fibers and industrial nonwoven fabrics because of their excellent mechanical properties. In recent years, demands for industrial fibers and industrial non-woven fabrics have increased, and not only improvement of mechanical properties but also improvement of elastic modulus and reduction of shrinkage ratio have been demanded.

As a polyamide fiber having excellent mechanical properties and elastic modulus and a small shrinkage ratio, for example, Patent Document 1 discloses a polyamide fiber composed of a resin composition containing a polyamide and a swelling fluoromica-based mineral. There is. However, the polyamide fiber of Patent Document 1 has a problem that the mechanical properties cannot be improved unless a large amount of an inorganic filler is blended, and since the inorganic filler is contained, the specific gravity becomes high. Further, even if the polyamide fiber of Patent Document 1 is discarded, the incineration residue remains in the ground. Furthermore, when spinning the polyamide fiber of Patent Document 1, there is a problem that pressurization and yarn unevenness are likely to occur and the quality of the obtained product is not stable.

JP-A-8-3818

It is an object of the present invention to provide a polyamide fiber and a non-woven fabric which have excellent mechanical properties and elastic modulus, a small shrinkage rate, a light weight, and an excellent spinnability.

As a result of intensive studies to solve such problems, the present inventors have found that the above object can be achieved by spinning a resin composition containing a specific cellulose fiber at the time of polymerization, and the present invention is achieved. Arrived

That is, the gist of the present invention is as follows.
(1) A polyamide fiber or a polyamide non-woven fabric comprising a resin composition containing 100 parts by weight of polyamide and 0.1 to 10 parts by weight of cellulose fibers having an average fiber diameter of 10 μm or less.
(2) The polyamide fiber or polyamide nonwoven fabric according to (1), wherein the polyamide has a relative viscosity of 2.0 or more.
(3) The polyamide fiber according to (1) or (2), wherein the degree of orientation of the cellulose fiber is 80% or more.

According to the present invention, it is possible to provide a polyamide fiber and a polyamide nonwoven fabric having excellent mechanical properties and elastic modulus, and having a small shrinkage rate. Since the polyamide fiber and the polyamide nonwoven fabric of the present invention do not contain an inorganic filler, they are lightweight, and even when discarded, the incineration residue does not remain in the ground, and when spinning, pressure and Thread unevenness is less likely to occur. Moreover, the polyamide fiber and the polyamide nonwoven fabric of the present invention can be suitably used for industrial applications and daily necessities.

The polyamide fiber and the polyamide nonwoven fabric of the present invention are made of a resin composition containing polyamide and cellulose fiber.

The polyamide used in the present invention is a polymer having an amide bond formed from an amino acid, a lactam or a diamine, and a dicarboxylic acid.

Examples of the amino acid include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid.

Examples of lactams include ε-caprolactam and ω-laurolactam.

Examples of the diamine include tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-/2,4,4-trimethylhexamethylenediamine, and 5 -Methylnonamethylenediamine, 2,4-dimethyloctamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5 -Trimethylcyclohexane, 3,8-bis(aminomethyl)tricyclodecane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl) Examples include propane and bis(aminopropyl)piperazine.

Examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid and 5-methylisophthalic acid. , 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, diglycolic acid.

Specific examples of the polyamide include polycaproamide (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), and polyhexa Methylenedodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), polyundecane amide (polyamide 11), polydodecanamide (polyamide 12), polytrimethylhexamethylene terephthalamide (polyamide TMHT), polyhexamethylene Terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polyhexamethylene terephthal/isophthalamide (polyamide 6T/6I), polybis(4-aminocyclohexyl)methandodecamide (polyamide PACM12), polybis(3- Methyl-4-aminocyclohexyl)methandodecamide (polyamide dimethyl PACM12), polymethaxylylene adipamide (polyamide MXD6), polynonamethylene terephthalamide (polyamide 9T), polydecamethylene terephthalamide (polyamide 10T), polyundeca Examples thereof include methylene terephthalamide (polyamide 11T) and polyundecamethylene hexahydroterephthalamide (polyamide 11T(H)), and copolymers or mixtures thereof may be used. Among them, polyamide 6, polyamide 66, polyamide 11, polyamide 12, and copolymers and mixtures thereof are preferable, and polyamide 6 and polyamide 66 are more preferable because the obtained polyamide fiber and polyamide nonwoven fabric have high mechanical properties. .

The above-mentioned polyamide is produced by a polymerization method which will be described later or in combination with a solid phase polymerization method.

The cellulose fibers used in the present invention include, for example, those derived from wood, rice, cotton, hemp, kenaf and the like, as well as those derived from organisms such as bacterial cellulose, valonia cellulose and ascidian cellulose. It also includes regenerated cellulose and cellulose derivatives.

In the present invention, in order to improve the mechanical properties of the obtained polyamide fiber or polyamide nonwoven fabric and reduce the shrinkage ratio, it is preferable to uniformly disperse the cellulose fiber in the fiber or the nonwoven fabric without aggregating. For that purpose, the cellulose fibers and the monomer constituting the polyamide must be uniformly mixed during the polymerization of the polyamide.

Further, in the present invention, it is desirable that the average fiber diameter of the cellulose fibers is as small as possible. The smaller the average fiber diameter of the cellulose fibers, the more strongly the cellulose fibers form a network structure in the matrix resin, and the better the mechanical properties. In addition, by uniformly dispersing, it is possible to reduce the shrinkage rate when using polyamide fibers or polyamide nonwoven fabric.

The average fiber diameter of the polyamide fibers and the cellulose fibers in the polyamide nonwoven fabric is required to be 10 μm or less, preferably 500 nm or less, more preferably 300 nm or less, and further preferably 200 nm or less. .. Cellulose fibers having an average fiber diameter of more than 10 μm are not preferable because the mechanical properties of the polyamide fibers and the polyamide nonwoven fabric are deteriorated and the shrinkage ratio is increased for the reasons described above. The lower limit of the average fiber diameter is not particularly limited, but it is preferably 3 nm or more in consideration of the productivity of cellulose fibers.

In order to set the average fiber diameter of the cellulose fibers in the polyamide fiber or the polyamide nonwoven fabric to 10 μm or less, it is preferable to use cellulose fibers to be blended with the polyamide having an average fiber diameter of 10 μm or less. Such cellulose fibers having an average fiber diameter of 10 μm or less are preferably microfibrillated by tearing the cellulose fibers. As means for microfibrillating, various crushing devices such as a ball mill, a stone mill, a high pressure homogenizer, a high pressure crushing device, and a mixer can be used. Examples of commercially available products of cellulose fiber include "Cerish" manufactured by Daicel Finechem.

As the cellulose fibers having an average fiber diameter of 10 μm or less, an aggregate of the cellulose fibers discharged as a waste thread in the process of manufacturing a fiber product using the cellulose fibers can be used. Examples of the manufacturing process of the fiber product include spinning, woven fabric, non-woven fabric production, and other processing of the fiber product. The aggregate of these cellulose fibers is a finely divided cellulose fiber since the cellulose fibers have been made into waste threads after undergoing these steps.

Bacterial cellulose fibers produced by bacteria can be used as the cellulose fibers having an average fiber diameter of 10 μm or less. For example, those produced as acetobacter acetic acid bacteria can be used. Cellulose fibers of plants are those in which molecular chains of cellulose are converged, and are formed by bundling very fine microfibrils, whereas cellulose fibers produced by acetic acid bacteria are originally 20 to 20 in width. It has a ribbon shape of 50 nm, and forms an extremely fine mesh shape as compared with plant cellulose fibers.

Furthermore, as a cellulose fiber having an average fiber diameter of 10 μm or less, for example, finely divided cellulose obtained by undergoing a washing process with water and a physical defibration process after oxidizing the cellulose fiber in the presence of an N-oxyl compound. Fibers may be used. Although there are various N-oxyl compounds, for example, 2,2,6,6-Tetramethylpiperidin-1-oxyl radical as described in Cellulose (1998) 5,153-164 is preferable. Such a compound is added to the aqueous reaction solution in a catalytic amount range.

To this aqueous solution, sodium hypochlorite or sodium chlorite is added as a co-oxidant, and an alkali metal bromide is added to proceed the reaction. An alkaline compound such as an aqueous solution of sodium hydroxide is added to maintain the pH at around 10, and the reaction is continued until no change in pH is observed. The reaction temperature may be room temperature. After the reaction, it is preferable to remove the N-oxyl compound remaining in the system. For washing, various methods such as filtration and centrifugation can be adopted. After that, the various crushing devices as described above are used to perform a physical defibration step to obtain micronized cellulose fibers. The cellulose fiber obtained by the above method becomes a cellulose fiber in which a part of the hydroxyl groups derived from cellulose is modified with a carboxyl group.

The aspect ratio ((average fiber length)/(average fiber diameter)), which is the ratio between the average fiber diameter and the average fiber length, of the cellulose fibers is preferably 10 or more, more preferably 50 or more, and 100 It is more preferable that the above is satisfied. When the aspect ratio is 10 or more, the mechanical properties of the obtained fiber and nonwoven fabric are likely to be improved.

The content of cellulose fibers needs to be 0.1 to 10 parts by mass, and preferably 0.1 to 5 parts by mass, based on 100 parts by mass of polyamide. If the content of cellulose fibers is less than 0.1 parts by mass with respect to 100 parts by mass of polyamide, sufficient mechanical properties cannot be obtained, which is not preferable. On the other hand, when the content of the cellulose fibers exceeds 10 parts by mass with respect to 100 parts by mass of polyamide, the spinnability is deteriorated, which is not preferable.

The relative viscosity of the resin composition containing the polyamide and the cellulose fiber was 2.0 when the concentration of the polyamide after removal of the cellulose fiber was measured at 1 g/100 mL at a temperature of 25° C. using 96% sulfuric acid as a solvent. Is preferably 5.0 to 5.0, more preferably 2.1 to 4.5. If the relative viscosity of the resin composition is less than 2.0, the mechanical properties may deteriorate. On the other hand, when the relative viscosity exceeds 5.0, the fluidity of the molten resin deteriorates, and the spinnability may decrease.

Cellulose fibers have a very high affinity with water, and the smaller the average fiber diameter, the better the state of dispersion in water can be maintained. Further, when water is lost, the cellulose fibers are strongly aggregated by hydrogen bonds, and once aggregated, it becomes difficult to take the same dispersed state as before aggregation. This tendency becomes more remarkable as the average fiber diameter of the cellulose fibers becomes smaller. Therefore, it is preferable that the cellulose fiber is mixed with the polyamide in a state of containing water. Therefore, in the present invention, it is preferable to adopt a method of obtaining a resin composition containing a cellulose fiber by carrying out a polymerization reaction of a monomer constituting a polyamide in the presence of a cellulose fiber containing water. By such a manufacturing method, it becomes possible to uniformly disperse the cellulose fibers in the polyamide fibers or the polyamide nonwoven fabric without aggregating.

A resin composition containing cellulose fibers can be produced by mixing a monomer constituting the polyamide with an aqueous dispersion of cellulose fibers having an average fiber diameter of 10 μm or less and conducting a polymerization reaction. In addition, when the additive which can be added to the resin composition mentioned later is added at the time of a polymerization reaction, a resin composition says the thing containing this additive.

The aqueous dispersion of cellulose fibers is a dispersion of cellulose fibers having an average fiber diameter of 10 μm or less in water, and the content of cellulose fibers in the aqueous dispersion is preferably 0.01 to 100 parts by mass. .. The aqueous dispersion of cellulose fibers can be obtained by stirring purified water and cellulose fibers with a mixer or the like. Then, an aqueous dispersion of cellulose fibers and a monomer constituting polyamide are mixed and stirred with a mixer or the like to form a uniform dispersion. Then, the dispersion liquid is heated, heated to 150 to 270° C., and stirred to cause a polymerization reaction. At this time, the water in the aqueous dispersion of cellulose fibers can be discharged by gradually discharging the steam when the dispersion is heated. During the polymerization of the above polyamide, a catalyst such as phosphoric acid or phosphorous acid may be added if necessary. After the completion of the polymerization reaction, it is preferable that the obtained resin composition is discharged and then cut into pellets.

When bacterial cellulose is used as the cellulose fiber, an aqueous dispersion of the cellulose fiber may be prepared by immersing the bacterial cellulose in purified water to replace the solvent. In the case of using the solvent-substituted bacterial cellulose, it is preferable that after the solvent replacement, the one adjusted to a predetermined concentration is mixed with the monomer constituting the polyamide and the polymerization reaction proceeds in the same manner as above.

In the above method, cellulose fibers having an average fiber diameter of 10 μm or less are subjected to the polymerization reaction as an aqueous dispersion, so that the cellulose fibers can be subjected to the polymerization reaction in a state of good dispersibility. Furthermore, the cellulose fibers that have been subjected to the polymerization reaction have improved dispersibility due to the interaction with the monomers and water during the polymerization reaction, and by stirring under the temperature conditions as described above, the fibers are aggregated together. It is possible to obtain a resin composition in which cellulose fibers having a small average fiber diameter are well dispersed. According to the method described above, the average fiber diameter of the cellulose fibers contained in the resin composition after the polymerization reaction may be smaller than that of the cellulose fibers added before the polymerization reaction.

Further, in the above method, the step of drying the cellulose fiber is not necessary, and the production can be performed without the step of scattering fine cellulose fibers, so that the resin composition can be obtained with good operability. Further, since it is not necessary to replace water with an organic solvent in order to uniformly disperse the monomer and the cellulose fiber, the handling is excellent and the discharge of chemical substances can be suppressed during the manufacturing process.

A polyamide fiber can be obtained by melt-molding a resin composition containing a polyamide and a cellulose fiber and, if necessary, stretching and heat-treating the obtained yarn or the like.

Examples of the melt molding method include a melt spinning method, a solution spinning method, and an electrospinning method. Among them, the melt spinning method having high versatility is preferably used.

For melt spinning, it is preferable to use a screw type extruder which is a melt extruder. Fibers can be obtained by spinning the polyamide used in the present invention at a melting point or higher through a spinneret nozzle. Furthermore, the yarn obtained by spinning is taken up by a take-up roller or the like, and if necessary, a heating or heat-retaining zone may be provided immediately below the nozzle, or a cooling zone such as a blowing chamber may be provided. You may apply an oil agent to the discharged thread.

The stretching is preferably carried out under heating conditions using a heating bath, heating steam spraying, a roller heater, a contact type plate heater, a non-contact type plate heater or the like. The draw ratio may be appropriately set depending on the composition of the polyamide used and the performance of the intended fiber, but it is preferably 2 times or more, more preferably 3 times or more. By stretching, the degree of orientation of the cellulose fibers is increased and the mechanical properties can be improved. The degree of orientation of the cellulose fibers is preferably 80% or more, more preferably 82% or more, even more preferably 85% or more. If the degree of orientation of the cellulose fibers is less than 80%, the mechanical properties of the fibers may deteriorate and the shrinkage ratio may increase. In the present specification, the degree of orientation of the cellulose fibers is within ±15 degrees of the cellulose fibers contained in the fibers, in the case of unstretched fibers, the extrusion direction of the fibers, and in the case of stretched fibers, the stretching direction is the standard. The ratio of oriented cellulose fibers is shown.

Further, if necessary, subsequent to the stretching, a constant length heat treatment, a tension heat treatment or a relaxation heat treatment may be further performed. In addition to the above-described two-step spinning and drawing method, undrawn yarn obtained by spinning may be continuously drawn.

A resin composition containing polyamide and cellulose fibers is laminated with undrawn yarn under the same conditions as the above-mentioned melt spinning method, or a known spunbond method, meltblowing method, flash spinning method, electrospinning method, wet non-woven fabric. A polyamide nonwoven fabric can be obtained by using a manufacturing method such as a method.

If necessary, additives and the like may be added to the polyamide fiber or the polyamide nonwoven fabric of the present invention. As a method of adding, the polyamide may be added at the time of polymerization, or the obtained polyamide may be melt-kneaded. Examples of the additives include other polymers different from polyamide, talc, swelling clay minerals, silica, alumina, fillers such as graphite, titanium oxide, pigments such as carbon black, antioxidants, heat stabilizers, and the like. Examples thereof include ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, flame retardant aids, colorants, plasticizers, lubricants, lubricants, crystal nucleating agents, and crystallization rate retarders. In particular, when an organic stabilizer such as polyhydric alcohol, a copper halide compound such as copper iodide, or an alkali metal halide compound such as potassium iodide is added as a heat stabilizer, melt retention stability during spinning is further improved. Therefore, it is preferable.

In the present invention, since the cellulose fiber having an average fiber diameter of 10 μm or less is contained instead of the inorganic filler, it is lightweight and the incineration residue does not remain in the ground even when it is discarded. Further, since it contains cellulose fibers having an average fiber diameter of 10 μm or less, even when spun, pressurization and yarn unevenness hardly occur, and the quality of the obtained product is excellent.

The polyamide fiber or polyamide nonwoven fabric of the present invention has excellent mechanical properties and elastic modulus, has a small shrinkage rate, and is lightweight, and therefore has a brush for polishing, a fishing net, a cord for a temporary payment machine, a gut, a toothbrush, a fishing line, It can be suitably used for industrial uses such as filters, separators, building materials, and daily necessities.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

A. Evaluation method The resin composition and the polyamide fiber used were evaluated by the following methods.

(1) Relative Viscosity The resin composition was dissolved in 96% sulfuric acid so that the concentration of polyamide after removal of cellulose fibers was 1 g/dL, and measured at 25° C. using an Ubbelohde viscometer.

(2) Fineness of polyamide fiber It was measured according to JIS L 1013 (chemical fiber filament yarn test method).

(3) Tensile strength and elastic modulus of polyamide fiber Polyamide fiber was cut into a length of 25 cm, and the obtained sample was measured according to JIS L 1013:2010.
The tensile test was carried out by using Autograph AG-1 type manufactured by Shimadzu Corporation at a tensile rate of 25 cm/min.

(4) Dry Heat Shrinkage of Polyamide Fiber The polyamide fiber was treated at 140° C. for 30 minutes and then measured according to JIS L 1013 (shrinkage/dry heat shrinkage).

(5) Average Fiber Diameter of Cellulose Fibers in Polyamide Fibers Polyamide fibers were cut using a freezing ultramicrotome, stained with sections, and then observed with a transmission electron microscope (JEM-1230, manufactured by JEOL Ltd.). It was The length of the cellulose fiber (single fiber) in the direction perpendicular to the fiber axis direction was measured from the electron microscope image. At this time, the maximum length in the vertical direction was defined as the fiber diameter. Similarly, the fiber diameters of 10 cellulose fibers (single fibers) were measured, and the average value of 10 fibers was calculated to be the average fiber diameter.
In addition, about the thing with a large fiber diameter of a cellulose fiber, the thing which cut out the 10-micrometer-thick section with a microtome, or a polyamide fiber as it is was observed using the stereomicroscope (SZ-40 by OLYMPUS). Then, the fiber diameter was measured from the obtained image in the same manner as above, and the average fiber diameter was determined.

(6) Fiber orientation degree in polyamide fiber From the image obtained by the same method as in (5), the inclination angle of the fiber with respect to the reference direction was measured at 20 points, and (the number of fibers having an inclination angle of ±15 degrees or more/the whole measured The number was calculated as x 100.

B. Raw materials The raw materials used are as follows.
(1) Polyamide monomer component/ε-caprolactam (manufactured by Ube Industries)

(2) Cellulose fiber/KY100G (Celish KY100G manufactured by Daicel Finechem Ltd., containing 10% by mass of cellulose fiber having an average fiber diameter of 125 nm)
KY110N (Celish KY110N manufactured by Daicel Finechem, Inc., containing 15% by mass of cellulose fibers having an average fiber diameter of 100 nm)
・Cotton short fiber (average fiber diameter 16μm)

Example 1
As an aqueous dispersion of cellulose fibers, Celish KY100G was used, purified water was added thereto, and the mixture was stirred with a mixer to prepare an aqueous dispersion having a content of cellulose fibers of 0.5% by mass.
100 parts by mass of this aqueous dispersion of cellulose fibers and 100 parts by mass of ε-caprolactam were further stirred and mixed with a mixer until a uniform dispersion was obtained. Subsequently, this mixed dispersion liquid was put into a polymerization apparatus, and then heated to 240° C. with stirring, while gradually releasing steam, the pressure was increased from 0 MPa to 0.5 MPa. After that, the pressure was released to atmospheric pressure, and a polymerization reaction was performed at 240° C. for 1 hour. When the polymerization was completed, the resin composition was discharged in a strand shape and cut to obtain pellets of the resin composition.
The obtained resin composition pellets were scoured with hot water at 95° C. and then dried to obtain dried resin composition pellets.
The obtained pellets of the dried resin composition were put into an extruder type single-screw extruder, and melt-spun at the spinning temperature shown in Table 1 using an 8-hole spinneret. After the spun yarn is cooled with water, it is taken up by the first roller and drawn between the first roller and the second roller while passing through an oven at a predetermined temperature so as to have a draw ratio of 4.2 times. Obtained.

Examples 2-6
As in Example 1, except that the type and content of the cellulose fibers were changed, and the polymerization time was changed so that the relative viscosity of the obtained resin composition was the value shown in Table 1, as shown in Table 1. The operation was performed to obtain dried pellets of the resin composition.
Polyamide fibers were obtained in the same manner as in Example 1 except that the obtained pellets of the resin composition were used and the spinning conditions shown in Table 1 were changed.

Comparative Example 1
The same operation as in Example 4 was carried out except that the cellulose fiber was not used to obtain dried resin composition pellets.
Using the obtained pellets of the dried resin composition, the same operations as in Example 4 were performed, and spinning and drawing were performed under the spinning conditions shown in Table 1 to obtain polyamide fibers.

Comparative example 2
Except for using the pellets of the dried resin composition obtained in Comparative Example 1, the same operations as in Example 6 were performed, and spinning and drawing were performed to obtain a polyamide fiber.

Comparative Example 3
As in Table 1, the same operation as in Example 4 was carried out except that the type of cellulose fiber was changed to obtain dried resin composition pellets.
Using the obtained pellets of the dried resin composition, the same operations as in Example 4 were carried out to carry out spinning and stretching to obtain polyamide fiber, but nozzle clogging and fiber breakage occurred, and polyamide fiber was obtained. Couldn't get

Comparative Example 4
The procedure of Example 4 was repeated except that the content of the cellulose fiber was changed to 15 parts by mass to carry out spinning and stretching to obtain a polyamide fiber. I couldn't get it.

Comparative Example 5
1 part by mass of the obtained cellulose fiber powder was mixed with 100 parts by mass of polyamide 6 (Nylon 6 BRF manufactured by Unitika Ltd., relative viscosity 2.9), and a twin-screw kneading extruder (PCM-30 manufactured by Ikegai Co., Ltd.) was used. Kneading was performed using a mold twin-screw extruder, screw diameter 30 mmφ), and the mixture was discharged, cut into pellets, and dried.
Using the obtained pellets of the dried resin composition, the same operations as in Example 4 were carried out to carry out spinning and stretching to obtain polyamide fiber, but nozzle clogging and fiber breakage occurred, and polyamide fiber was obtained. Couldn't get

Comparative Example 6
The same operation as in Example 4 was carried out except that the polymerization time was changed so that the relative viscosity of the resin composition became 1.8, to obtain dried resin composition pellets.
Using the obtained pellets of the dried resin composition, the same operations as in Example 4 were carried out to carry out spinning and drawing to obtain polyamide fibers, but fiber breakage frequently occurred and fibers were obtained. could not.

Table 1 shows the raw materials of the polyamide fibers obtained in Examples and Comparative Examples, the spinning conditions, and the characteristic values of the obtained polyamide fibers.

The polyamide fibers obtained in Examples 1 to 5 and 6 have higher tensile strength, lower elastic modulus, and dry heat than the polyamide fibers of Comparative Examples 1 and 2 each made of a resin composition containing no cellulose fiber. The shrinkage was small. Moreover, the spinnability was also excellent.

Since the polyamide fiber of Example 6 was a fiber having a low draw ratio, the degree of orientation of the cellulose fiber was low, the elastic modulus was rather high, and the dry heat shrinkage was rather large.

Claims (3)

A polyamide fiber or a polyamide non-woven fabric, comprising a resin composition containing 100 parts by weight of polyamide and 0.1 to 10 parts by weight of cellulose fibers having an average fiber diameter of 10 μm or less. The polyamide fiber or polyamide nonwoven fabric according to claim 1, wherein the polyamide has a relative viscosity of 2.0 or more. The polyamide fiber according to claim 1 or 2, wherein the degree of orientation of the cellulose fiber is 80% or more.