JPH10266020A - Conjugate monofilament and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide-based conjugate monofilament having excellent impact strength and suitable for marine raw materials and industrial raw materials and provide a method for efficiently producing the conjugate monofilament. SOLUTION: This conjugate monofilament is composed of an at least two layer conjugate structure comprising a core part and a sheath part and each layer is composed of a polyamide-based resin having >=2.5 relative viscosity and melting point of the core-part polymer is >=180 deg.C and melting point of the sheath-part polymer is higher by 5-100 deg.C than the milting point of the core- part polymer. The method for producing the conjugate monofilament comprises carrying out orientation process in final stage at a temperature satisfying the formula Tc-10 deg.C <=Te<=Ts+30 deg.C [Te = orientation temperature ( deg.C); Tc = melting point (C) of the core-part polymer; Ts = melting point ( deg.C) of the sheath-part polymer] in a method for melt-spinning and cooling at least two kinds of polyamide-based resins by using a conjugate spinning apparatus and successively orienting the spun yarn so that whole draw ratio is >=5.0 times by one stage to multi-stage orientation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite monofilament having excellent impact strength and particularly suitable for marine materials and industrial materials, and a method for efficiently producing the composite monofilament.

[0002]

2. Description of the Related Art Synthetic resin monofilaments, especially polyamide-based resin monofilaments, are tough, have excellent flexibility and transparency, and have useful properties such as moderate straining. It is widely used for marine materials and various industrial materials.

[0003] However, since the polyamide resin monofilament has a large wire diameter, a normal manufacturing method tends to cause a difference in fiber structure in the cross-sectional direction of the monofilament. Has been a bottleneck because it cannot be expressed.

[0004] As a prior art for improving the structural difference of the polyamide resin monofilament, (A) At least a two-layer composite structure of a core portion and a sheath portion, and each layer is made of a polyamide resin, Composite yarn wherein the relative viscosity of the core polymer is 2.8 or more and the apparent viscosity of the sheath polymer is smaller than the apparent viscosity of the core polymer
No. 9-144615) and (B) a high knot strength composite monofilament in which a plurality of island components composed of a thermoplastic resin having a small flexibility are dispersed in a sea component composed of a thermoplastic polymer having a large flexibility. JP-A No. 62-45712) and (C) a polyamide monofilament comprising a polycaproamide-based polyamide and having a concentric three-layer structure of inner soft-medium rigid-outer soft (Japanese Patent Laid-Open No. 8-284022) Has been already proposed.

[0005] That is, the composite yarn of (A) aims to increase the knot strength by lowering the degree of orientation of the surface layer portion, and the (B) monofilament of high knot strength increases the knot strength due to the specificity of the composite structure. However, in any case, the uniformity of the fiber structure in the cross-sectional direction was still insufficient.

Although the polyamide monofilament (C) has a concentric three-layer structure to achieve excellent linear strength and high knot strength, it also has a uniform fiber structure in the cross-sectional direction. However, it was not always satisfactory.

Therefore, any of the conventional polyamide-based resin monofilaments is insufficient in terms of uniformity of the fiber structure in the cross-sectional direction, and thus does not have physical properties such as sufficient impact strength. In fact, the improvement was desired.

[0008]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying to solve the above-mentioned problems in the prior art.

Accordingly, an object of the present invention is to provide a polyamide-based composite monofilament having excellent impact strength and particularly suitable for marine materials and industrial materials, and a method for efficiently producing the composite monofilament. is there.

[0010]

In order to achieve the above object, the composite monofilament of the present invention has at least a two-layer composite structure of a core and a sheath, and each layer has a relative viscosity of 2.5 or more. Wherein the melting point of the core polymer is 180 ° C. or higher, and the melting point of the sheath polymer is 5 to 100 ° C. higher than the melting point of the core polymer.

In the composite monofilament of the present invention, the relative viscosity of the polyamide resin constituting the sheath polymer is larger than the relative viscosity of the polyamide resin constituting the core polymer. Weight ratio is 95/5
４０40/60 and the impact strength is 1.
It is desirable to satisfy any one of the conditions of 1 GPa or more, and in that case, it is possible to expect a more excellent effect to be exhibited.

Further, in the method for producing a composite monofilament of the present invention, at least two kinds of polyamide resins are melt-spun and cooled by using a composite spinning apparatus, and subsequently, in one to multiple stages, the total draw ratio is 5.0. In the method of stretching so as to be twice or more, the final stretching step is performed at a temperature satisfying the following formula (1). Tc−10 ° C. ≦ Te ≦ Ts + 30 ° C. (1) where, Te = stretching temperature (° C.) Tc = melting point of core polymer (° C.) Ts = melting point of sheath polymer (° C.)

[0013]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide resin core-sheath composite monofilament composed of a low melting polyamide resin as a core polymer and a high melting polyamide resin as a sheath polymer at an appropriate temperature. It is characterized by stretching, which makes it possible to optimize the fluidity of the polymer in the inner and outer layers at the time of stretching and makes the fiber structure such as the degree of orientation of the inner and outer layer polymers more uniform. It is possible to realize a composite monofilament having much improved strength.

Hereinafter, the present invention will be described in detail.

The polyamide resin constituting the core polymer and the sheath polymer of the composite monofilament of the present invention has a melting point of 180 ° C. or more and a relative viscosity of 2.5 or more. Are polycaproamide (hereinafter referred to as nylon 6), caproamide / hexamethylene adipamide copolymerized polyamide (hereinafter nylon 6/6)
6), polyhexamethylene adipamide (hereinafter referred to as nylon 66), polyhexamethylene sebacamide (hereinafter referred to as nylon 610), polyhexamethylene dodecamide (hereinafter referred to as nylon 612), polyundecanamide (Hereinafter referred to as Nylon 11), and polymeta-xylene adipamide (hereinafter referred to as MX Nylon), but are not limited thereto.

The polyamide resins used in the present invention include, for example, pigments, dyes, light stabilizers, ultraviolet absorbers,
Various additives such as an antioxidant, a crystallization inhibitor, and a plasticizer can be added in the polymerization step, after the polymerization, or immediately before spinning, as long as the desired performance is not excluded.

Regarding the combination of the polyamide resin constituting the core polymer and the sheath polymer, the melting point of the polyamide resin constituting the core is 180 ° C. or more, and the melting point of the polyamide resin constituting the sheath is: There is no particular limitation as long as it is 5 to 100 ° C. higher than the melting point of the core polymer, but it is more preferable that the relative viscosity of the polyamide resin constituting the sheath is higher than that of the core.

If the difference between the melting points of the polyamide resin constituting the sheath and the core is less than 5 ° C., the effect of improving the impact strength of the composite monofilament is undesirably reduced.

When the relative viscosity of the polyamide resin constituting the core portion and the sheath portion is less than 2.5, respectively, and when the melting point of the polyamide constituting the core portion is less than 180 ° C., the physical properties such as tensile strength are increased. If the relative viscosity of the sheath polymer is lower than that of the core polymer, the effect of improving the impact strength decreases, which is not preferable. In the composite monofilament of the present invention, the composition ratio of the core and the sheath is such that the weight ratio of the core and the sheath is 95/5 to 40/6.
0, and particularly preferably in the range of 90/10 to 50/50. If the ratio is outside these ranges, the effect of improving the impact strength is reduced, which is not preferable.

The shapes of the monofilament and the core of the composite monofilament of the present invention are not necessarily required to have a circular cross section, but it is most industrially advantageous to set the circular cross section from the viewpoint of convenience in manufacturing a nozzle. In addition, the core-sheath structure of the composite monofilament is usually a two-layer core-sheath structure for convenience in production, but does not exclude a multilayer core-sheath structure of three or more layers.

The composite monofilament of the present invention can be efficiently produced by the method described below.

First, when melt-spinning the composite monofilament, ordinary conditions using a core-sheath composite spinning apparatus can be adopted, and the polymer temperature is 200 to 3
Conditions such as 00 ° C., extrusion pressure: 10 to 500 kg / cm ³ , die hole diameter: 0.1 to 5 mm, and spinning speed: 0.3 to 100 m / min can be appropriately selected.

The monofilaments spun from each extruder and subjected to a core-in-sheath composite in a die are cooled in a cooling bath after passing through a short gas zone, and a liquid inert to the polymer is used as a cooling medium. Usually, water is used. Also,
The cooling temperature is usually preferably around 10 ° C. to prevent spherulite generation.

The cooled and solidified composite monofilament is
Subsequently, it is sent to the first stretching step. As the atmosphere (bath) for stretching and heat setting, polyethylene glycol,
A heated heat medium bath such as glycerin and silicone oil, a dry hot gas bath, and a pressurized steam bath are used.

Next, single-stage or multi-stage stretching is performed so that the total stretching ratio becomes 5.0 times or more. Here, it is essential that the final stretching process is performed at a temperature satisfying the following formula (1). It is. Tc−10 ° C. ≦ Te ≦ Ts + 30 ° C. (1) where, Te = stretching temperature (° C.) Tc = melting point of core polymer (° C.) Ts = melting point of sheath polymer (° C.)

Here, the total stretching ratio is less than 5.0 times or at least the stretching temperature in the final stretching step is (Tc-10).
C) below, physical properties such as tensile strength of the obtained composite monofilament cannot be sufficiently satisfied,
If the stretching temperature in the final stage stretching step exceeds (Ts + 30 ° C.), the monofilament will be melted during stretching, which is not preferable.

After the single-stage or multi-stage stretching, an appropriate constant length,
Relaxation heat treatment can also be performed.

The composite monofilament of the present invention thus obtained exhibits excellent physical performance with an impact strength of 1.1 GPa or more, so that it can be used for fishery materials such as fishing lines and fishing nets and various industrial materials. Very useful.

[0029]

EXAMPLES The present invention will be further described below with reference to examples. The evaluation of monofilaments in the examples was performed according to the following method.

(1) Impact strength: Tensile impact strength (Kg) was measured by a pendulum impact tester manufactured by Shimadzu, and tensile impact strength (GPa) was determined as the tensile impact strength per unit area. The tensile impact strength (Kg) was measured using a pendulum hammer for 50 kg · cm and a load cell of 10 kg, and the test length was 300 m.
m, and the measured value was determined by reading the height of the peak that appeared on the chart of the visit graph. (The number of measurements was five, and the average was shown.) (2) Melting point: Measured according to the DSC method described in JIS-K7121.

(3) Relative viscosity: Measured according to the method (sulfuric acid method) described in 4.4.1 of JIS-K6810.

Example 1 Nylon 6/6 having a caproamide / hexamethylene adipamide ratio of 85/15
6 (melting point: 194 ° C., relative viscosity: 4.2 ... polymer A)
1) as a core component (80 parts by weight), nylon 6 (melting point:
222 ° C., relative viscosity: 4.4. Polymer B1) as a sheath component (20 parts by weight) was melted at 280 ° C. by an extruder-type composite spinning machine, spun through a die having a pore diameter of 0.8 mm, and further spun at 10 ° C. Cooled in a water bath.

Next, the undrawn yarn was drawn in a polyethylene glycol drawing bath at 200 ° C. by 6.5 times to obtain a monofilament.

Subsequently, by passing through a hot water bath at 95 ° C. at a treatment magnification of 0.95 times and performing a heat treatment, a composite monofilament having a diameter of 0.20 mm and a composite ratio shown in Table 1 was obtained.

Example 2 Polymer A as in Example 1
No. 1 was used as a core component (80 parts by weight), and polymer B1 was used as a sheath component (20 parts by weight).

Next, the undrawn yarn is drawn 4.6 times (E1) in a first-stage steam drawing bath at 100 ° C.
The film was stretched 1.5 times (E2) in the second-stage dry heat bath at 0 ° C. to obtain a monofilament having a total draw ratio (E1 × E2) of 6.9 times.

Subsequently, by passing through a dry heat bath at 180 ° C. at a treatment magnification of 0.92 times and performing heat treatment, a composite monofilament having a diameter of 0.20 mm and a composite ratio shown in Table 1 was obtained.

Example 3 Nylon 6/6 having a caproamide / hexamethylene adipamide ratio of 90/10
6 (melting point: 199 ° C., relative viscosity: 4.2 ... polymer A)
2) as a core component (60 parts by weight) and nylon 66 (melting point: 264 ° C., relative viscosity: 4.6... Polymer B2) as a sheath component (40 parts by weight) at 290 ° C. with an extruder-type composite spinning machine. It was melted, spun through a die having a hole diameter of 0.8 mm, and further cooled in a water bath at 10 ° C.

Next, the undrawn yarn is drawn 4.5 times (E1) in a first-stage steam drawing bath at 100 ° C.
The film was stretched 1.5 times (E2) in a second-stage dry heat bath at 0 ° C. to obtain a monofilament having a total draw ratio (E1 × E2) of 6.8 times.

Subsequently, by passing through a dry heat bath at 180 ° C. at a processing magnification of 0.90 times and performing heat treatment, a composite monofilament having a diameter of 0.20 mm and a composite ratio shown in Table 1 was obtained.

Example 4 An extruder-type composite spinning machine using the polymer B1 used in Example 1 as a core component (80 parts by weight) and the polymer B2 used in Example 3 as a sheath component (20 parts by weight) At 290 ° C with a pore size of 0.8
The fiber was spun through a 10 mm diameter die and further cooled in a 10 ° C. water bath.

Next, the undrawn yarn is drawn 4.6 times (E1) in a first-stage steam drawing bath at 100 ° C.
The film was stretched 1.3 times (E2) in a second-stage dry heat bath at 0 ° C. to obtain a monofilament having a total draw ratio (E1 × E2) of 6.0 times.

Subsequently, by passing through a dry heat bath at 180 ° C. at a treatment magnification of 0.90 times and performing a heat treatment, a composite monofilament having a diameter of 0.20 mm and a composite ratio shown in Table 1 was obtained.

Comparative Example 1 Polymer A used in Example 1
Independently, a monofilament having a diameter of 0.20 mm was obtained by employing the spinning conditions described in Table 1 alone.

Comparative Example 2 Polymer A used in Example 3
The monofilaments having a diameter of 0.20 mm were obtained by using 2 alone and employing the spinning conditions described in Table 1.

Comparative Example 3 Polymer B used in Example 1
Independently, a monofilament having a diameter of 0.20 mm was obtained by employing the spinning conditions described in Table 1 alone.

Comparative Example 4 Polymer B used in Example 3
The monofilaments having a diameter of 0.20 mm were obtained by using 2 alone and employing the spinning conditions described in Table 1.

Comparative Example 5 Polymer A used in Example 1
1 as a core component (80 parts by weight) and nylon 6/66 (melting point: 196 ° C., relative viscosity: 4.4... Polymer A3) having a caproamide / hexamethylene adipamide ratio of 87/13 as a sheath component ( 20 parts by weight) and employing the spinning conditions described in Table 1, a monofilament having a diameter of 0.20 mm was obtained.

Comparative Examples 6 and 7 In Example 2, except that the stretching temperature in the second step was set to 180 ° C. and 260 ° C.
The same manufacturing method as in Example 2 was employed.

Comparative Example 8 The same manufacturing method as in Example 2 was used except that the ratio of the core component polymer A1 was 97 parts by weight and the ratio of the sheath component polymer B1 was 3 parts by weight. Adopted.

Comparative Example 9 The same manufacturing method as in Example 2 was used except that the ratio of the core component polymer A1 was changed to 30 parts by weight and the ratio of the sheath component polymer B1 was changed to 70 parts by weight. A composite monofilament having a diameter of 0.20 mm was obtained.

Table 1 also shows the results of evaluating the characteristics of the composite monofilaments obtained in Examples 1 to 4 and Comparative Examples 1 to 9 as monofilaments.

[0053]

[Table 1] As is clear from the results in Table 1, the core portion and the sheath portion have at least a two-layer structure, each layer is made of a polyamide resin having a relative viscosity of 2.5 or more, and the melting point of the core portion polymer is 180 ° C. As described above, the monofilament of the present invention (Examples 1 to 4), wherein the melting point of the sheath polymer is 5 to 100 ° C. higher than the melting point of the core polymer, has an excellent impact strength of 1.1 GPa or more. Has physical performance.

On the other hand, the monofilaments of various polyamide resins alone (Comparative Examples 1 to 4) and the composite monofilaments in which the core / sheath component polymer had a difference in melting point of less than 5 ° C. (Comparative Example 5) were compared with the composite monofilaments of the present invention. And the impact strength is inferior.

The core / sheath weight ratio is 95/5 to 4
The composite monofilament out of the range of 0/60 (Comparative Examples 8 and 9) and the composite monofilament in which the drawing temperature in the final stage drawing step was out of the range of the above-mentioned formula (1) (Comparative Example 6, No. 7) was melted during stretching or did not sufficiently satisfy the effects intended by the present invention.

[0056]

As described above, since the composite monofilament of the present invention has an unprecedented high impact strength, it is extremely useful for fishery materials such as fishing lines and fishing nets and various industrial materials.

Further, according to the method for producing a composite monofilament of the present invention, a composite monofilament having the above characteristics can be produced efficiently.

Claims (5)

[Claims] Claims: 1. A core part and a sheath part having at least a two-layer composite structure, wherein each layer is made of a polyamide resin having a relative viscosity of 2.5 or more, and the melting point of the core part polymer is 180 ° C. or more, A composite monofilament, wherein the melting point of the sheath polymer is 5 to 100 ° C. higher than the melting point of the core polymer. 2. The composite monofilament according to claim 1, wherein the relative viscosity of the polyamide resin constituting the sheath polymer is higher than the relative viscosity of the polyamide resin constituting the core polymer. 3. The weight ratio of the core to the sheath is 95/5 to 40.
3. The method according to claim 1, wherein the distance is in the range of / 60.
2. The composite monofilament according to item 1. 4. The composite monofilament according to claim 1, wherein the composite monofilament has an impact strength of 1.1 GPa or more. 5. The method according to claim 1, wherein the composite spinning device comprises at least two fibers.
In a method of melt-spinning, cooling, and subsequently stretching one kind of polyamide resin in one stage or multiple stages so that the total stretching ratio becomes 5.0 times or more, the stretching process in the final stage satisfies the following formula (1). The method for producing a composite monofilament according to any one of claims 1 to 4, wherein the method is performed at a temperature. ◎ Tc−10 ° C. ≦ Te ≦ Ts + 30 ° C. (1) where, Te = stretching temperature (° C.) Tc = melting point of core polymer (° C.) Ts = melting point of sheath polymer (° C.)