JP2941176B2 - Polyvinylidene fluoride monofilament and its production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention, fishing line, fishing net, strength properties for use in rope consists particularly excellent polyvinylidene fluoride of knot strength (referred PVDF) polymer Mo
Nofilament and its manufacturing method .

[0002]

2. Description of the Related Art PVDF polymers have a higher specific gravity, a refractive index close to that of water, a lower water absorption and a lower surface tension compared to nylon and polyester, so that water repellency is good, weather resistance and chemical resistance. It is used as a monofilament for fishing lines, fishing nets, ropes, etc. because of its excellent properties. However, PVDF-based monofilaments have a lower knot strength than nylon monofilaments, and therefore, an improvement in knot strength has been desired.

Conventionally, various attempts have been made to improve the knot strength of PVDF-based monofilaments. For example, a method by improving a drawing method such as multi-stage drawing (Japanese Patent Laid-Open No. 60-2090).
No. 09, No. 60-215810), a method of forming a core-sheath composite monofilament of PVDF polymer and nylon (JP-A-56
-134215) and PVD with apparent viscosity difference between core and sheath
There is a method of producing a composite monofilament composed of an F-based polymer (JP-A-59-144614). However, the improvement of the drawing method is largely affected by the components constituting the monofilament and the structure thereof, and there is a limit in improving the knot strength. Also, in the method of forming a core-sheath composite monofilament of a PVDF polymer and nylon, the obtained monofilament is hardly essentially a PVDF monofilament, and the large specific gravity, which is one of the features of the PVDF monofilament, is the weight ratio of nylon. Decreases as the PVDF increases, and furthermore, the PVDF basically has a different molecular structure.
And nylon, interfacial delamination between the core and sheath occurs,
There is a problem that a monofilament satisfying the target yarn quality performance cannot be obtained. In the case of a core-sheath conjugate fiber using a PVDF-based polymer having a difference in apparent viscosity between a low viscosity sheath and a high viscosity core, the temperature used for drawing is appropriate for the high viscosity polymer of the core component. However, the low-viscosity polymer of the sheath component is subjected to a high-temperature heat treatment, and as a result, there has been a problem that the sheath component may deteriorate.

Further, in the case of producing a multilayer monofilament, a production technique using multiple components is generally used. Among components constituting each layer in the production process, a component having a small discharge amount has a flow rate in a nozzle pack. Is very slow, so that deterioration due to heat progresses, and there is a problem that the quality of the obtained monofilament is deteriorated or colored.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides strength characteristics,
In particular, an object of the present invention is to provide a PVDF-based monofilament having excellent knot strength.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve such problems, and as a result, have found that the cross section has a three-layer structure of a specific ratio composed of PVDF polymers having different logarithmic viscosities. And improved the strength characteristics, especially the knot strength, and found that by using the same polymer for the components constituting the inner and outer layers during spinning, thermal degradation of the polymer could be suppressed. The present inventors have found the suitable spinning conditions for producing a monofilament having a three-layer structure with improved yarn properties, and have reached the present invention.

That is, the gist of the present invention is as follows. Nodular strength of PVDF polymer is 4.0g
/ D or more monofilament whose cross section has a concentric three-layer structure of inner soft-medium hard-outer soft, with soft layer having a logarithmic viscosity of 0.70 to 1.20 and rigid layer having a logarithmic viscosity of 1.25 to 1.45. Wherein the polyvinylidene fluoride monofilament satisfies the conditions of the following formulas (a) and (b). (a) 0.60r ₀ ≦ r ₁₁ ≦ 0.98r ₀ (b) 0.10r ₀ ≦ r ₂₁ ≦ 0.40r ₀ (r ₀ is the radius of the monofilament, r ₁₁ is the radius of the outer circumferential circle of the middle layer, and r ₂₁ is the inner radius of the middle layer. Indicates the radius of the circumference.) PV
A monofilament made of a DF-based polymer and having a knot strength of 4.0 g / d or more and having a concentric three-layer structure of inner rigid-medium soft-outer rigid in its cross section, and a soft layer having a logarithmic viscosity of 0.
A polyvinylidene fluoride monofilament, characterized in that the rigid layer is composed of a polymer having a logarithmic viscosity of 1.25 to 1.45 and satisfies the conditions of the following formulas (c) to (d). (c) 0.85r ₀ ≦ r ₁₂ ≦ 0.98r ₀ (d) 0.50r ₀ ≦ r ₂₂ ≦ 0.75r ₀ (r ₀ is the radius of the monofilament, r ₁₂ is the radius of the outer peripheral circle of the middle layer, and r ₂₂ is the inner radius of the middle layer. Indicate the radius of the circumference circle.) In the production of monofilaments having the above three-layer structure through the melt-spinning and drawing processes, in the drawing process, the first-stage drawing of 3.0 to 6.0 times at a temperature of 120 to 180 ° C Then, at the temperature of 140 to 200 ° C, which is higher than that of the first stretching, stretching is performed at the second and subsequent stages so that the total stretching ratio becomes 5.5 to 7.5 times. Strength
A method for producing a polyvinylidene fluoride monofilament, wherein the filament is 4.0 g / d or more. The solution described above
In the melt-spinning process, the two types of polymers (C) and (D) are separated by an introduction plate (1), separated and filtered by a filtration plate (2), and then weighed by a weighing plate with a specific number of holes of the same diameter. The measurement and division are performed in (3), and then the polymer (C) is focused to the composition ratio of the inner layer and the outer layer by the focusing plate (4), and the polymer (C) is used as the core component and the polymer (D) in the composite intermediate plate (5). ) Is formed as a sheath component, and a concentric three-layer composite flow is formed by the composite spinneret (6) with the core-sheath composite flow and the polymer (C) divided for the outer layer composition. Melt-spinning using a spinneret pack discharged from the spinneret hole to form a three-layer structure.
A method for producing a redene-based monofilament . The logarithmic viscosity (η _inh ) in the present invention is a value measured at a temperature of 30 ° C. using dimethylformamide as a solvent.

Hereinafter, the present invention will be described in detail. In the present invention, the PVDF-based polymer means a PVDF homopolymer and a PVDF copolymer containing vinylidene fluoride as a main component. Specific examples of the PVDF copolymer include a PVDF copolymer containing tetrafluoroethylene, monochlorotrifluoroethylene, vinyl fluoride, hexafluoropropylene, perfluoroisopropoxyethylene, or the like as a copolymer component. And PVDF
The system polymer may be a mixture of two or more kinds of polymers, and contains a heat stabilizer, a coloring agent, an antioxidant, a plasticizer, and the like for the purpose of improving the spinning property or the thread property, transparency, and the like. May be.

[0009] monofilament of the present invention are those having the three-layer structure consisting of a soft layer and Tsuyoshiso, eta _inh of soft layer polymer 0.70 to 1.20, the eta _inh of the polymer Tsuyoshiso 1.25
It must be in the range of ~ 1.45. If this condition is not satisfied, the spinnability deteriorates and the yarn quality performance becomes insufficient. That is, η _{inh of the} soft polymer is 0.
If it is less than 70, the spinning properties will be poor, and if it exceeds 1.20, the flexibility of the monofilament will be insufficient and the knot strength will be low. Further, if the η _inh of the polymer of the rigid layer is less than 1.25, the strength of the monofilament decreases, and if it exceeds 1.45, the spinning properties deteriorate.

In the monofilament of the present invention, the polymer of the soft layer is a PVDF copolymer containing 85 to 98 mol% of vinylidene fluoride units containing the above copolymerization component, and the polymer of the rigid layer is a PVDF homopolymer. It is preferable because monofilaments having good yarn forming properties and good yarn quality can be obtained.

The first monofilament of the present invention is shown in FIG.
It has a concentric three-layer structure of inner soft-medium hard-outer soft as shown in (1), and satisfies the conditions of the above formulas (a) and (b). Since this monofilament has a soft layer in the center, the rigid layer can be deformed at a lower temperature in the process of deformation in the fiber axis direction at the time of stretching, compared to the core-sheath two-layer structure,
Since stretching can be performed at a lower temperature, thermal deterioration of the soft layer on the surface during stretching can be prevented.

The second monofilament of the present invention has an inner rigid-medium soft-outer rigid concentric three-layer structure as shown in FIG. 1 (2), and has the above-mentioned formulas (c) to (d). It satisfies the condition of Since the monofilament has a rigid layer on the surface, the middle soft layer is prevented from deteriorating due to heat at the time of stretching, and becomes more flexible because the middle soft layer has a high temperature.

If the requirements for the thickness of each layer, (a)-(b) or (c)-(d), are not satisfied, in addition to the requirements for η _inh of the polymer of the soft layer and the rigid layer, good yarn quality is obtained. It does not become a monofilament.

It is possible to use three kinds of polymers and each layer can be made of a different kind of polymer. In this case, however, the residence time of a small amount of the component in the spinneret pack becomes long, and the thermal deterioration of the component proceeds. It is desirable that two layers constitute three layers.

In FIG. 1, A represents a rigid layer and B represents a soft layer. The radius of the monofilament and the radius of the outer and inner circles of the middle layer can be measured from the cross section of the monofilament. For convenience, a method of converting from the composition ratio of the polymer in each layer can be used.

Next, a method for producing the monofilament of the present invention will be described. First, an undrawn monofilament having a three-layer structure is obtained by melt-spinning using PVDF-based polymers having different η _inh . At this time, the spinning temperature is 230 ~
Suitably the temperature is 320 ° C, preferably 250-280 ° C. If the spinning temperature is too low, the polymer will not melt completely or the melt viscosity will be extremely high, making it difficult to fibrillate. On the other hand, if the spinning temperature is too high, thermal decomposition of the polymer will occur, which is not preferable. The spun yarn is cooled using a liquid or a gas, and is preferably -10 to 80 ° C, preferably 0 to 50 ° C.
It is desirable to use the liquid for cooling. If the temperature of the cooling liquid is too low, it is difficult to control the temperature and workability. If the temperature is too high, the cooling will be insufficient and the yarn quality of the finally obtained monofilament will be inferior.

Next, the cooled and solidified monofilament is drawn after being wound once or without being wound. In the present invention, it is important that stretching is performed under appropriate conditions, and the stretching point is not shifted.
In the liquid or gas at the temperature of the above, perform the first-stage stretching of 3.0 to 6.0 times, and then in the liquid or gas at a temperature of 140 to 200 ° C, which is higher than the first-stage stretching, the total stretching ratio becomes 5.5 to 7.5 times. Thus, it is necessary to perform stretching in the second and subsequent stages. At this time, the total stretching ratio is set to be higher than the first-stage stretching ratio. When the total draw ratio is less than 5.5 times, the yarn quality characteristics of the obtained monofilament, particularly the linear strength is inferior, 7.5
If it is larger than twice, a whitening phenomenon occurs, and a satisfactory monofilament cannot be obtained. After stretching, heat treatment is performed as necessary to obtain a product.

Next, a spinneret pack suitable for spinning a monofilament forming three layers with two kinds of polymers will be described with reference to FIGS. FIG.
1 shows the configuration of the entire spinneret pack. The polymer C and the polymer D are supplied to the introduction plate 1 in a fixed amount. Polymer C forms the inner and outer layers, and polymer D forms the middle layer. Filter polymers C and D on filtration plate 2 and then distribute evenly.

FIGS. 3 to 6 show an example of a porous plate and a spinneret for producing six monofilaments in which the composition ratio of the inner layer to the outer layer is 3: 1 by weight. In the measuring plate 3, the filtered polymer C is distributed to 24 holes having the same hole diameter as shown in FIG. 3, and the 6 holes are passed through the focusing plate 4 as they are in the focusing plate 4 (FIG. 4), and the 18 holes are passed through the focusing plate 4. By converging and uniformly distributing to one third of the six holes, the composition ratio is regulated to 18: 6.

The six holes in the preceding paragraph correspond to the nozzle pack R side in FIG. 2 and pass through the composite intermediate plate 5 (FIG. 5) as it is.
It reaches the composite spinneret 6 (FIG. 6). The six holes obtained by converging the eighteen holes into six holes correspond to the nozzle pack L side in FIG. 2, and the composite intermediate plate 5 (FIG. 5) forms a core-sheath composite structure with the polymer D. Thereafter, the polymer C reaching the composite spinneret 6 (FIG. 6) on the side of the spinneret pack R in FIG. 2 constitutes the outermost layer of the core-sheath composite structure. Then, a monofilament having a concentric three-layer structure is spun from the composite spinneret 6.

In order to obtain the composition ratio of the inner layer and the outer layer according to the purpose, the measuring plate 3 (FIG. 3) in the die pack of FIG.
This is possible by changing the number of holes of the focusing plate 4 (FIG. 4), the composite intermediate plate 5 (FIG. 5), the composite spinneret 6 (FIG. 6) or the focusing number of the focusing plate 4 (FIG. 4). Further, the composition ratio or the fiber diameter with the middle layer can be changed by changing the supply amounts of the polymer C and the polymer D and the hole diameter of the spinneret.

The cross section on the R side in FIG.
The L-side section corresponds to the section on the L-plane in FIGS. 3 to 6. In addition, black portions in FIGS. 2 to 6 indicate contact surfaces with other plates.

When three layers are composed of two kinds of polymers in this manner, three layers can be formed by two extruder-type melt extruders, and the spinneret pack is simplified, and
The cost can be reduced as compared with the case where the composite is formed by using a kind of polymer.

[0024]

[Function] When knotting monofilament and applying external force,
At the knot part of the monofilament, there is a part where compression and tensile stress parallel to the fiber axis direction are simultaneously applied, and if stress concentration occurs at this part, the fiber breaks down and as a result, the fiber cuts Leads to. This stress concentration can be reduced by making the monofilament itself flexible. However, when the entire monofilament is made flexible, the linear strength decreases. Since the monofilament of the present invention has a portion exhibiting high linear strength (high-viscosity rigid layer) and a portion providing flexibility (low-viscosity soft layer), it is recognized that both the linear strength and the knot strength are improved. . That is, in the case of the inner soft-medium hard-outer soft of the first invention, the surface is a soft low-viscosity layer, so the effective area under which stress is applied increases, and the knot strength can be improved. In the case of the inner rigid-medium soft-outer rigid of the second invention, the soft layer acts like a cushion of the rigid layer, and the knot strength can be improved, and in any case, due to the high-viscosity rigid layer. It is possible to maintain a strong straight line.

[0025]

Next, the present invention will be described specifically with reference to examples. Examples 1-4 A PVDF copolymer obtained by copolymerizing 4.8 mol% of a PVDF homopolymer having η _inh = 1.38 and a hexafluoropropylene component having η _inh = 1.00 was heated at 270 ° C. and 250 ° C., respectively, using an extruder spinning apparatus. Melted. The molten polymer is extruded in a metered manner so that the inner layer, the middle layer, and the outer layer have a composition ratio of three layers described in Table 1.
The polymer was divided into an inner layer and an outer layer by a spinneret pack having the configuration shown in FIG. 2, and composite spinning was performed using a composite spinneret having a hole diameter of 0.9 mm. Cool the spun yarn in a water bath at 35 ° C,
An undrawn yarn was obtained. This undrawn yarn is drawn 5.10 times in a 165 ° C. glycerin bath, then drawn 1.32 times while passing through a 175 ° C. heating zone, and the total draw ratio is 6.75 times.
Next, 0.95 by passing through a heating zone at 150 ° C.
A double relaxation heat treatment was performed.

Examples 5 to 7 Monofilaments were produced in the same manner as in Example 1 using the PVDF homopolymer having η _inh = 1.28 and the PVDF copolymer having η _inh = 1.00 so as to have the composition ratio shown in Table 1.

Comparative Examples 1 and 2 Monofilaments were produced by spinning and stretching in the same manner as in Example 1 so as to have the composition ratios shown in Table 1.

Comparative Examples 3 and 4 Monofilaments were produced in the same manner as in Example 1 using the PVDF homopolymer having η _inh = 1.28 and the PVDF copolymer having η _inh = 1.00 so as to have the composition ratio shown in Table 1.

Comparative Examples 5 to 6 The same PVDF homopolymer and PVDF copolymer as those of Example 1 were used, and the components were similarly extruded so as to have the composition ratio of the inner layer and the outer layer shown in Table 1, and a spinneret for composite spinning was used. Then, the core-sheath composite spinning was performed. Subsequent steps were performed in the same manner as in Example 1 to obtain a monofilament having a core-sheath two-layer structure.

Comparative Example 7 A PVDF homopolymer having η _inh = 1.29 was melted at a temperature of 270 ° C. using an extruder-type spinning apparatus, and the pore size was adjusted.
After spinning through a 0.9 mm die, the spun yarn was cooled in a water bath at 35 ° C. to obtain an undrawn yarn. The stretching step was performed in the same manner as in Example 1 to obtain a single-layer monofilament.

COMPARATIVE EXAMPLE 8 A PVDF copolymer obtained by copolymerizing 4.8 mol% of a hexafluoropropylene component having η _inh = 1.00 was melted at a temperature of 250 ° C. using an extruder type spinning apparatus, and a pore diameter of 0.9 was obtained.
After spinning through a millimeter die, the spun yarn was cooled in a water bath at 35 ° C. to obtain an undrawn yarn. This undrawn yarn is subjected to the first-stage drawing so as to have the same draw ratio or relaxation ratio as in Example 1.
C. glycerin bath, second stage stretching 165 ° C. heating zone,
The relaxation heat treatment was performed using a heating zone at 150 ° C. for stretching and heat treatment to obtain a single-layer monofilament.

COMPARATIVE EXAMPLE 9 4.8 mol% of a PVDF homopolymer having η _inh = 1.46 and a hexafluoropropylene component having η _inh = 1.00 were copolymerized to give P.
The VDF copolymer was melted using an extruder type spinner at temperatures of 280 ° C and 250 ° C, respectively. The inner layer, the middle layer,
The mixture was extruded in a metered manner so as to have a composition ratio of the outer layer, and was made into a yarn in the same manner as in Example 3 to obtain a composite monofilament.

Comparative Example 10 A PVDF homopolymer having η _inh = 1.23 and a PVDF copolymer obtained by copolymerizing 4.8 mol% of a hexafluoropropylene component having η _inh = 0.67 were used at 270 ° C. and 230 ° C., respectively, using an extruder spinning apparatus. Melted at temperature. This molten polymer was formed into a yarn in the same manner as in Example 1 to obtain a composite monofilament.

Table 1 shows the yarn quality performance of the monofilaments obtained in the above Examples and Comparative Examples.

[0035]

[Table 1]

As is clear from Table 1, the monofilaments of the examples of the present invention exhibited excellent values in both the linear strength and the knot strength. The strength was low or unsatisfactory.

[0037]

According to the present invention, a PVDF-based monofilament having excellent linear strength and high knot strength is provided. In particular, when the same polymer is used for the inner layer and the outer layer having a three-layer structure, the spinning apparatus can be simplified, and thermal degradation of the polymer can be suppressed, and a monofilament exhibiting excellent yarn quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a monofilament of the present invention, wherein (1) is a monofilament having an inner soft-medium rigid-outer soft structure, and (2) is a monofilament having an inner rigid-medium soft-outer rigid structure. Show.

FIG. 2 shows a spinneret pack used in the production method of the present invention .
It is a schematic diagram showing the overall configuration of a click.

FIG. 3 is a plan view (top view) of a measuring plate 3 of the spinneret pack of FIG. 2;

FIG. 4 is a plan view (top view) of a focusing plate 4 of the spinneret pack of FIG. 2;

5 is a plan view (top view) of a composite intermediate plate 5 of the spinneret pack of FIG. 2;

6 is a plan view (top view) of the spinneret 6 of the spinneret pack of FIG. 2;

[Explanation of symbols]

 A Soft layer B Rigid layer 1 Introducing plate 2 Filtration plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D01F 6 / 12,8 / 10 D01D 5/34

Claims (5)

(57) [Claims] 1. A monofilament consisting of a polyvinylidene fluoride polymer and having a knot strength of 4.0 g / d or more and having a concentric three-layer structure of inner soft-medium hard-outer soft in its cross section. The layer has a logarithmic viscosity of 0.70 to 1.20, and the rigid layer is composed of a polymer having a logarithmic viscosity of 1.25 to 1.45.
A polyvinylidene fluoride monofilament characterized by satisfying the conditions (a) and (b). (a) 0.60r ₀ ≦ r ₁₁ ≦ 0.98r ₀ (b) 0.10r ₀ ≦ r ₂₁ ≦ 0.40r ₀ (r ₀ is the radius of the monofilament, r ₁₁ is the radius of the outer peripheral circle of the middle layer, and r ₂₁ is the inside of the middle layer. Indicates the radius of the circumference.) 2. A monofilament made of a polyvinylidene fluoride-based polymer and having a knot strength of 4.0 g / d or more, and having a concentric three-layer structure of inner rigid-medium soft outer rigid in its cross section, The layer has a logarithmic viscosity of 0.70 to 1.20, and the rigid layer is composed of a polymer having a logarithmic viscosity of 1.25 to 1.45.
A polyvinylidene fluoride monofilament which satisfies the conditions of (c) to (d). (c) 0.85r ₀ ≦ r ₁₂ ≦ 0.98r ₀ (d) 0.50r ₀ ≦ r ₂₂ ≦ 0.75r ₀ (r ₀ is the radius of the monofilament, r ₁₂ is the radius of the outer peripheral circle of the middle layer, and r ₂₂ is the inside of the middle layer. Indicates the radius of the circumference.) 3. The polymer constituting the soft layer is a polyvinylidene fluoride copolymer having a vinylidene fluoride unit content of 85 to 98 mol%, and the rigid layer is a polyvinylidene fluoride homopolymer. Monofilament. 4. Through the melt-spinning and drawing process, claim
In producing a monofilament having a three-layer structure described in 1, 2, or 3 , in the stretching step, the first-stage stretching is performed at a temperature of 120 to 180 ° C. and 3.0 to 6.0 times, and then a higher temperature than the first-stage stretching is performed. At 140-200 ° C, the total draw ratio is
The second and subsequent stages are stretched to 5.5-7.5 times,
A method for producing a polyvinylidene fluoride monofilament, wherein a linear strength is 5.0 g / d or more and a knot strength is 4.0 g / d or more. 5. The method according to claim 4, wherein:
The two types of polymers (C) and (D) are divided by the introduction plate (1), separated and filtered by the filtration plate (2), and then weighed by the measurement plate (3) having a specific number of holes with the same diameter. , Split, and then polymerized by focusing plate (4)
(C) is focused on the composition ratio of the inner layer and the outer layer,
In (5), a core-sheath composite stream is formed with the polymer (C) as the core component and the polymer (D) as the sheath component, and the composite spinneret (6) separates this core-sheath composite stream and the polymer separated for the outer layer composition. After forming a concentric three-layer composite flow in (C), the mixture is discharged from the nozzle hole.
Using a spinneret pack designed to form a three-layer structure
Polyvinylidene fluoride monofilament that is melt-spun
Manufacturing method .