JPH0754210A - Polyvinylidene fluoride monofilament and production thereof - Google Patents

Abstract

PURPOSE:To obtain the filament having a high tensile strength and a high knot strength suitable for a fishing line, and excellent in uniformity, impact- resistant strength and abrasion resistance by specifying the average birefringence, surface birefringence and surface roughness of the monofilament. CONSTITUTION:A monofilament of polyvinylidene fluoride polymer occupied with >=80wt.% of vinylidene fluoride structural unit and having an intrinsic viscosity etainh of >=0.8 is characterized by having a diameter D of 0.05-0.6mm, an average birefringence DELTAnT of 33X10<-3> to 41X10<-3>, a surface birefringence DELTAnS of 27X10<-3> to 33X10<-3>, a difference (DELTAnT-DELTAnS) of >=3X10<-3> between the average birefringence and the surface birefringence, a surface maximum- minimum roughness of <=400nm, a two-dimensional mean square roughness of <=55nm, a tensile strength of <=(-2.0XD-6.1), and a knot strength of >=(-3.0XD+4.8). The monofilament is obtained by thermally treating the monofilament of the polyvinylidene fluoride polymer for a short time in a non- stretched state and subsequently drawing the heat-treated monofilament in a pressed and heated steam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinylidene fluoride monofilament having high tensile strength and high knot strength, and a method for producing the same. Specifically, it has high tensile strength and high knot strength, which are mainly suitable for fishing lines.
The present invention relates to a polyvinylidene fluoride monofilament having excellent uniformity, high impact strength and high abrasion resistance, and a method for efficiently producing the polyvinylidene fluoride monofilament.

[0002]

2. Description of the Related Art Polyvinylidene fluoride monofilaments are excellent in toughness, impact resistance, transparency and light resistance, yet have a high specific gravity and are easily sunk in water, and have a refractive index close to that of water and surface reflection of light in water is extremely high. Since it has few characteristics and is hard to see, it has excellent properties especially for fishing lines and fishing nets.

However, in the applications for these fishing lines and fishing nets, there is always quality unevenness, thinner and stronger,
Further, it is required to have characteristics of good wear resistance and good impact resistance.

Conventionally, as a polyvinylidene fluoride monofilament, for example, Japanese Patent Publication No. 58-39922,
Japanese Examined Patent Publication No. 3-5001, Japanese Patent Publication No. 47-40573
Typical examples are those described in JP-A-55-45834.

That is, the polyvinylidene fluoride monofilament described in Japanese Patent Publication No. 58-39922 is blend-spun with a polymer having an intrinsic viscosity index (ηinh) of 1.3 or more and a polymer having a viscosity of 1.2 or less in two stages. It is obtained by a stretching method.

The polyvinylidene fluoride monofilament described in Japanese Examined Patent Publication No. 3-50001 is mainly composed of a stretched yarn of a thermoplastic resin monofilament made of vinylidene fluoride resin, which is higher than the melting point on the low temperature side of the surface constituting resin. 1.0 ~ in a liquid at a temperature not exceeding 30 ° C above the melting point or in an inert gas at 200 ~ 500 ° C.
It was obtained by a method of performing a tension heat treatment for a short time of 0.1 to 8 seconds at a draw ratio of 2.0 times.

Further, the polyvinylidene fluoride monofilament described in Japanese Patent Publication No. 47-40573 is
It was obtained by a method of passing through an atmosphere of 200 to 240 ° C. at a position 7 to 30 cm below the die, quenching in a liquid, and continuously stretching.

Furthermore, the polyvinylidene fluoride monofilament described in JP-A-55-45834 was passed through the atmosphere at 200 to 500 ° C. for 2 to 50 cm under the die for 0.1 to 10 seconds. After that, it is obtained by a method of cooling in a liquid and continuously stretching.

The techniques described in JP-B-47-40573 and JP-A-55-45834 are stable by cooling in a liquid after passing through a high temperature atmosphere under a spinneret. The purpose is to make yarn.

The techniques described in JP-B-58-39922, JP-B-3-50001, JP-B-47-40573, and JP-A-55-45834 are the strengths of the polyvinylidene fluoride monofilament itself. It is a fairly excellent technology for improving

[0011]

However, the strength of the polyvinylidene fluoride monofilament particularly when it is used as a fishing line is lower than that of the nylon monofilament, so that it is required to form a higher strength monofilament. It is required to improve not only the above-mentioned characteristics but also various characteristics useful as a fishing line.

The present invention has been achieved as a result of studies for improving the above-mentioned conventional technique and realizing a polyvinylidene fluoride monofilament satisfying the above-mentioned required performance.

Therefore, an object of the present invention is to provide a polyvinylidene fluoride monofilament having a high tensile strength and a high knot strength, which are mainly suitable for fishing lines, and have excellent uniformity, high impact strength and high abrasion resistance. An object of the present invention is to provide a method for efficiently producing vinylidene chloride monofilament.

[0014]

Means for Solving the Problems As a result of various studies to achieve the above object, the present inventors have found that the average birefringence, surface birefringence and surface roughness of a polyvinylidene fluoride monofilament are controlled within specific ranges. , By specifying the fiber surface structure, or by setting the average birefringence, wear resistance, and surface compression micro displacement value of the polyvinylidene fluoride monofilament within a specific range, It was found that it is possible to realize a vinylidene monofilament, and that such a polyvinylidene fluoride monofilament can be easily obtained by performing a high-temperature short-time heat treatment in an unstretched yarn state, and then subjecting it to pressurized heating steam stretching. The invention was reached.

That is, the polyvinylidene fluoride monofilament of the present invention has a vinylidene fluoride structural unit of 80.
A monofilament composed of a polyvinylidene fluoride-based polymer having an intrinsic viscosity index (ηinh) of 0.8 or more, which occupies weight% or more, and the monofilament has a diameter (D) of 0.05 to 0.6 mm and an average. Birefringence (ΔnT)
Is 33 × 10 ^{−3 to} 41 × 10 ⁻³ , surface birefringence (ΔnS)
Is 27 × 10 ^{−3 to} 33 × 10 ⁻³ , the difference (ΔnT−ΔnS) between the average birefringence and the surface birefringence is 3 × 10 ⁻³ or more, the surface maximum / minimum roughness is 400 nm or less, and the two-dimensional square is obtained. It has a fiber surface structure having an average roughness of 55 nm or less, a tensile strength (TT) of [−2.0 × D + 6.1] or more (where D is the diameter described above), and a knot strength (KT). [-
3.0 × D + 4.8] or more (where D is the diameter described above) (first invention).

In the polyvinylidene fluoride monofilament of the present invention, the vinylidene fluoride constitutional unit accounts for 80% by weight or more, and the intrinsic viscosity index (ηinh) is 0.8.
A monofilament made of the above polyvinylidene fluoride polymer, wherein the monofilament has an average birefringence (ΔnT) of 33 × 10 ^{−3 to} 41 × 10 ⁻³ , an abrasion resistance of 180 to 250 times, and a load. It is characterized in that the surface layer has a small displacement value of 17 to 25 μm at 200 gf (second invention).

Further, in the method for producing a polyvinylidene fluoride monofilament of the present invention, the vinylidene fluoride constituent unit accounts for 80% by weight or more, and the intrinsic viscosity index (ηin
h) 0.8 or more polyvinylidene fluoride-based polymer is melt-spun out, cooled and solidified in an inert liquid at 20 ° C. or lower, and then in an inert gas at 250 to 500 ° C. for 0.1 to 5 seconds. By carrying out heat treatment at a high temperature for a short time, an unstretched monofilament having a surface birefringence (ΔnS) of 1 × 10 ⁻³ or less is obtained. Then, this unstretched monofilament is pressurized and heated with a stretching ratio of 5.6 times or more by steam heating. (3rd invention).

The polyvinylidene fluoride monofilaments in the first and second inventions have a high tensile strength and a high knot strength in common, and are excellent in uniformity, high impact strength and high abrasion resistance. It exhibits various characteristics.

Both of the polyvinylidene fluoride monofilaments in the first and second inventions can be efficiently produced by the method of the third invention.

The polyvinylidene fluoride used in the present invention is
80% by weight or more of the repeating structural unit of the molecular chain is made of vinylidene fluoride, and the copolymerization component can be contained in the range of 20% by weight or less. Examples of the copolymerization component include tetrafluoroethylene, trifluoromonochloroethylene, and hexafluoropropylene.

Here, when polyvinylidene fluoride contains a copolymerization component in an amount of more than 20% by weight, the crystallinity is excessively lowered and a high strength monofilament may not be obtained, which is not suitable.

The polyvinylidene fluoride used in the present invention preferably has an intrinsic viscosity index (ηinh) measured with a 0.4 g / cc solution of dimethylformamide of 0.8 or more, particularly 1.0 or more. .

When the intrinsic viscosity index of polyvinylidene fluoride is less than 0.8, it is difficult to form a high-strength monofilament because of its low degree of polymerization, and high-strength drawing is performed to obtain a high-strength monofilament. If this happens, yarn breakage is likely to occur, and problems with toughness are likely to occur. Therefore, if the intrinsic viscosity index is less than 0.8, a high-strength monofilament suitable for fishing line cannot be obtained, which is not preferable.

On the other hand, when the above-mentioned intrinsic viscosity index (ηinh) of polyvinylidene fluoride has a high viscosity exceeding 2.0,
Discharge spots are likely to occur during spinning and tend to cause diameter spots and strength spots in the filament length direction, which is not preferable.

Therefore, in the polyvinylidene fluoride used in the present invention, the intrinsic viscosity index (ηinh) measured with a 0.4 g / cc solution of dimethylformamide is in the range of 1.0 to 2.0 in consideration of the spinnability. It is preferable to be present, and it is particularly preferable to be in the range of 1.1 to 1.6.

The polyvinylidene fluoride used in the present invention contains additives such as pigments, dyes, light stabilizers, ultraviolet absorbers, antioxidants, crystallization inhibitors and plasticizers.
It may be contained within a range that does not impair the effects of the present invention.

The polyvinylidene fluoride monofilament of the present invention has a diameter (D) of 0.05 to 0.6 mm.
If the thickness is less than 0.05 mm, the rigidity of the monofilament itself is insufficient, and the tensile strength and knot strength required for fishing line cannot be satisfied. On the other hand, if it exceeds 0.6 mm, the cooling will be insufficient, and the high tensile strength and high knot strength which are the objects of the present invention cannot be obtained, which is not preferable.

First, the fiber structural characteristics of the polyvinylidene fluoride monofilament of the first invention will be described.

The polyvinylidene fluoride monofilament of the first invention has the following fiber structural characteristics.

Diameter (D) = 0.05 to 0.6 mm, average birefringence (ΔnT) = 33 × 10 ^{−3 to} 41 × 10 ⁻³ , surface birefringence (ΔnS) = 27 × 10 ^{−3 to} 33 × 10 ⁻³ , (ΔnT) ≧ (ΔnS) + 3 × 10 ⁻³ , surface maximum / minimum roughness = 400 nm or less, two-dimensional root-mean-square roughness = 55 nm or less, and relationship between tensile strength (TT) and diameter (D): (TT) ≧ −
2.0 × D + 6.1 Relationship between Nodule Strength (KT) and Diameter (D): (KT) ≧ −
3.0 x D + 4.8

That is, the average birefringence (ΔnT) is high,
The surface (surface layer portion) has a low birefringence (ΔnS), and is characterized in that the surface has an extremely smooth and uniform morphology due to the surface maximum / minimum roughness and the two-dimensional root mean square roughness described above.

Here, the average birefringence (ΔnT) is 33 × 1.
If it is less than 0 ^-3 , it is not possible to obtain a polyvinylidene fluoride monofilament excellent in durability, which is the object of the present invention to significantly improve the tensile strength and impact strength. When the average birefringence (ΔnT) is to exceed 41 × 10 ⁻³ , it is necessary to draw at a high draw ratio in the drawing process, and yarn breakage occurs or stable drawing cannot be performed. Is not preferable.

The average birefringence (ΔnT) is preferably 3
It is 5 × 10 ⁻³ or more, and when it is 35 × 10 ⁻³ or more, the tensile strength and impact strength can be further improved.

The surface birefringence (ΔnS) is 27 × 1.
If it is less than 0 ^-3 , the surface is too soft and surface damage due to rock misalignment or the like becomes large and the fatigue resistance when applied to fishing lines and the like deteriorates, which is not preferable. Further, when it is desired to obtain a surface birefringence (ΔnS) of more than 33 × 10 ⁻³ , it is not preferable because the surface becomes less flexible and the knot strength tends to decrease.

The relationship between the average birefringence (ΔnT) and the surface birefringence (ΔnS) is (ΔnT) ≧ (ΔnS) + 3 ×
If it does not satisfy 10 ⁻³ , the surface layer portion becomes harder than the inner layer portion, cracks easily occur, and the knot strength decreases, which is not preferable.

In the polyvinylidene fluoride monofilament of the present invention, the high birefringence of the inner layer shows that the molecular chains are well oriented in the fiber axis direction, which contributes to the development of high tensile strength.

On the other hand, the surface layer portion having a low birefringence forms a flexible layer and protects the structure of the inner layer portion which exhibits high tensile strength. Furthermore, stress concentration at the time of knotting is relaxed and cracks are less likely to occur, which contributes to the development of high knotting strength.

When the surface layer portion having a low birefringence is thicker than 1/10 of the diameter from the surface of the fiber, for example, a diameter of 0.21 mm and a tensile strength of 5 g / d or more of 94u high strength, high knot monofilament. Is difficult to obtain and is not preferable.

The polyvinylidene fluoride monofilament of the first aspect of the invention has a maximum and minimum roughness of 400 nm or less obtained by calculating the difference between the maximum value and the minimum value of the surface irregularities, and is a standard when the flat surface of the monofilament is fitted. Since the two-dimensional root mean square roughness for which the deviation is obtained is 55 nm or less, an extremely smooth surface is formed, and there is no groove in the fiber axis direction, and the surface is uniform, so the contact area is large. It has a high coefficient of friction, tightens well when forming a knot that is indispensable for fishing lines, does not loosen the knot, has less scratches, and is less likely to crack, resulting in high knot strength. Can be expected.

Further, the polyvinylidene fluoride monofilament of the first aspect of the present invention has the characteristics that the surface morphology is smooth, so that the water drainage is good, and that the operability such as the handling of the rod is good, first of all for the rod. ing.

Next, the fiber structural characteristics of the polyvinylidene fluoride monofilament of the second invention will be described.

The polyvinylidene fluoride monofilament of the second aspect of the invention is specified under physical condition conditions different from those of the first aspect of the invention and exhibits the same effects as the first aspect of the invention. It has fiber structural characteristics.

Average birefringence (ΔnT) = 33 × 10 ^{−3 to} 41 × 10 ⁻³ , abrasion resistance = 180 to 250 times, surface layer compression minute displacement value at load of 200 gf = 17 to 25 μm
m

That is, the average birefringence (ΔnT) is high,
The surface is characterized by high abrasion resistance, and by setting the surface layer compression minute displacement value within a specific range, the surface is extremely smooth and has a uniform morphology.

The average birefringence (ΔnT) of the polyvinylidene fluoride monofilament of the second aspect of the present invention has a great influence on important fishing line characteristics such as tensile strength, abrasion resistance, and impact knot strength.

That is, the average birefringence (ΔnT) is 33 × 1.
When it is less than 0 ^-3 , it is not possible to obtain a polyvinylidene fluoride monofilament having a high strength, particularly excellent impact knot strength, and suitable for fishing lines.

The average birefringence (ΔnT) is 41 × 10.
If it exceeds ^-3 , the surface of the monofilament becomes rough, and the durability especially when used as a fishing line is lowered, and the impact knot strength tends to be lowered, and particularly the average birefringence (ΔnT) is 42 × 10 ^-3. When it is larger than the above range, the impact knot strength is drastically reduced, and it becomes impossible to obtain a polyvinylidene fluoride monofilament suitable as a fishing line.

The wear resistance of the polyvinylidene fluoride monofilament of the second aspect of the invention has a great influence on the important fishing line properties, such as tensile strength and impact knot strength.

The abrasion resistance referred to in the second invention is 1
OD × 50 mmφ, which is a monofilament with a load of / 20 × D (fineness) coated with sandpaper # 320.
The stainless steel rod of No. 1 is placed on the surface rotating at 180 times / minute, and the monofilament is further moved at a traverse speed of 70 mm / minute (traverse width of 35 mm), which is a value defined by the number of rotations until cutting. .

If the abrasion resistance is less than 180 times, both the durability and the impact knot strength are poor, so that a polyvinylidene fluoride monofilament suitable for fishing line cannot be obtained.

If the abrasion resistance exceeds 250 times, the surface layer portion of the monofilament is excessively crystallized and the impact knot strength tends to be lowered, so that a polyvinylidene fluoride monofilament suitable as a fishing line cannot be obtained, which is not preferable.

The stretch orientation adopted in the conventional method is effective for improving the high tensile strength and the high knot strength of the polyvinylidene fluoride monofilament, but it is not always effective from the viewpoint of impact knot strength and is highly advanced. When oriented, larger fibrils occur in the surface layer than fibrils due to the presence of relatively large spherulites in the inner layer that is gradually cooled compared to the surface layer, which causes a significant decrease in impact knot strength. You will be invited.

Therefore, in the second aspect of the present invention, a polyvinylidene fluoride monofilament having a desired impact knot strength is obtained by forming the polyvinylidene fluoride monofilament into a structure having a surface layer, particularly a surface with a smaller flaw. That is, the unstretched monofilament is subjected to a high-temperature short-time heat treatment to the unstretched monofilament in a fluid having a temperature equal to or higher than the melting point so as to relax the surface portion of the surface layer but not most of the inner layer. The fact that it can be obtained by adding is found.

That is, the polyvinylidene fluoride monofilament of the second aspect of the present invention is characterized in that the surface layer compression minute displacement value at a load of 200 gf is in the range of 17 to 25 μm.

From the viewpoint of impact knot strength, it is considered that the larger the compressive micro-displacement value is, the more the stress concentration on the surface layer due to bending is alleviated. Therefore, the more preferable range is 17 to 22 μm.

Here, when the above-mentioned small displacement value of compression exceeds 25 μm, the inner layer portion of the monofilament is softened and the tensile strength and abrasion resistance, which are important characteristics as a fishing line, are reduced. Is not preferable because the surface layer becomes too hard and impact knot strength due to bending decreases.

The intrinsic viscosity index (ηinh) and monofilament diameter (D) of the polyvinylidene fluoride monofilament constituting the second invention are 0 for the same reason as described in the first invention. It is preferably 0.8 or more and in the range of 0.05 to 0.6.

However, the polyvinylidene fluoride monofilament of the second aspect of the present invention has high tensile strength and high knot strength as well as excellent uniformity, high impact strength, as well as the polyvinylidene fluoride monofilament of the first aspect of the present invention. It has both high wear resistance and various other properties suitable for fishing lines.

The above-mentioned two types of polyvinylidene fluoride monofilaments of the present invention can be manufactured by the manufacturing method of the third invention. The manufacturing method will be described below, including specific conditions.

That is, in producing the polyvinylidene fluoride monofilament of the present invention, first, a polyvinylidene fluoride polymer chip in which the constituent unit of vinylidene fluoride is 80% by weight or more and the intrinsic viscosity index (ηinh) is 0.8 or more. Is supplied to a melt spinning machine, melted at a high temperature such as 260 ° C., and spun from a spinneret to obtain a spun monofilament.

Next, the spun monofilament is heated in a heating atmosphere (eg, 300 ° C.) provided immediately below the spinneret.
After passing through nitrogen gas heated to a moderate temperature or an atmosphere length of 150 mm filled with an inert gas such as heated steam, immediately pass through a low-temperature liquid at a temperature of 20 ° C or less to rapidly solidify by cooling. To form an unstretched monofilament.

As the low temperature liquid in the above cooling and solidification,
Water, polyvinylidene fluoride such as glycerin and polyethylene glycol and inert liquids are used.

Subsequently, the cooled and solidified unstretched monofilament is passed through a washing bath of warm water or water,
After removing the cooling medium adhering to the surface of the monofilament, water droplets on the surface of the monofilament are removed with an inert gas such as nitrogen or air at 20 ° C or less, and the unstretched monofilament is continuously inactivated at 250 to 500 ° C. Heat treatment for a short time in a high temperature fluid.

When the fluid used for the short-time high-temperature heat treatment is a gas, an inert gas such as heated air or heated nitrogen is used. However, since these have low thermal conductivity, they are generally at 250 to 500 ° C. Temperature required, preferably 3
Temperatures of 80 ° C to 490 ° C are used.

On the other hand, when the fluid used for the high-temperature heat treatment for a short time is a liquid, an inert liquid such as polyethylene glycol, glycerin and silicone oil is used. Since the orientation relaxation proceeds too much and becomes unsuitable, the upper limit of the temperature is usually 50 ° C above the melting point of polyvinylidene fluoride.
It is preferred to use a temperature not higher than.

In the short-time high-temperature heat treatment, the time for contacting the unstretched monofilament with the high-temperature fluid varies depending on the temperature and the type of fluid, but is generally about 0.1 to 5 seconds, preferably 4 seconds or less. .

In the short-time high-temperature heat treatment, only the surface layer of the unstretched monofilament is once melted, and the orientation is relaxed so that the birefringence of the surface of the unstretched monofilament becomes 1.0 × 10 ⁻³ or less.

The thickness of the unstretched monofilament surface layer depends on the diameter of the monofilament, but is usually 3
It may be in the range of up to 15 μm.

The monofilament which has been subjected to the above-mentioned short time high temperature heat treatment is then continuously and continuously subjected to a pressure of 1 Kg / cm ² G or more,
The temperature is maintained at 150 ° C. or higher, and the steam is sent into a pressure chamber filled with steam and subjected to pressurized heating steam stretching.

In the pressure chamber, the inlet and the outlet through which the monofilament passes are sealed by a sealing mechanism composed of slits so that the leakage of steam is prevented as much as possible and the steam pressure is maintained.

The stretching ratio in the pressurized heating steam stretching is such that the average birefringence (ΔnT) of the stretched polyvinylidene fluoride monofilament is 33 × 10 ⁻³ or more, preferably 3
Magnification of 5 × 10 ^-3 or more and 41 × 10 ^-3 or less,
That is, it is generally performed at 5.6 times or more.

In the case of the first-stage stretching, all the stretching is carried out in the pressure chamber. In the case of the multi-stage stretching, at least the first stage stretching is carried out in the pressure chamber, and the second and subsequent stages are stretched by using a non-contact heater or the like. Can be done.

In the above-mentioned pressurized heating steam drawing, the monofilament is drawn at a high draw ratio of 5.6 times or more, but since the heated heating steam drawing is performed with good thermal efficiency, the drawing tension is low and the surface layer of the monofilament is formed. Surface birefringence (Δ
nS) is 27 × 10 ^{−3 to} 33 × 10 ⁻³ .

The monofilament is heat-treated for a short time at a high temperature when it is not stretched, so that only the surface layer is once melted. Therefore, the stretch tension is low even when stretched at a high ratio, and the obtained stretched monofilament is The surface morphology is very smooth and the maximum and minimum surface roughness is 400n
m or less and the two-dimensional root mean square roughness is 55 nm or less.

Similarly, the obtained drawn monofilament has a very smooth surface morphology and an abrasion resistance of 180-2.
The surface layer compression minute displacement value at a load of 200 gf 50 times is in the range of 17 to 25 μm.

The polyvinylidene fluoride monofilament of the present invention thus obtained has high tensile strength and knot strength,
And has excellent impact resistance and abrasion resistance. The tensile strength, knot strength, and impact resistance all change depending on the diameter of the monofilament, and the larger the diameter is, the lower the polyvinylidene fluoride monofilament of the present invention is. One of the characteristics is that the sex ratio is low.

That is, the diameter (D) of the monofilament
The relationship between the tensile strength (TT) and the knot strength (KT) is as shown in (I) and (II) below.

TT ≧ −2.0D + 6.1 (I) KT ≧ −3.0D + 4.8 (II)

For example, when the diameter is 0.21 mm (No. 1.5), tensile strength: 5.9 g / d, knot strength: 4.8 g / d
d, impact strength: 5.5 g / d, impact nodule: 3.9 g / d
With a diameter of 0.37 mm (No. 5), tensile strength:
5.8 g / d, knot strength: 4.6 g / d, impact strength:
An excellent monofilament with 5.1 g / d and impact node: 3.6 g / d is obtained.

Here, it is important that the tensile strength and the knot strength are high at the same time in order to maintain the characteristic that the strength is high regardless of how the knot is tied when used as a fishing line. That is, when a relatively small bending strain is applied, it is close to the tensile strength, and when a large bending strain is applied, it is almost represented by the knot strength.

Further, the polyvinylidene fluoride monofilament of the present invention is also excellent in abrasion resistance. For example, when evaluated by the sandpaper method, the monofilament of the present invention has a cutting abrasion resistance of 2.5 times or more that of the conventional one. Indicates the number of times. In this way, durability with excellent wear resistance,
This is because the polyvinylidene fluoride monofilament of the present invention has a unique fiber structure.

Another feature of the polyvinylidene fluoride monofilament of the present invention is that it has high tensile rigidity while being flexible against bending. For example, when used as a fishing line, this has the characteristic that it is easy to detect "atari".
It is extremely advantageous in that it also satisfies the contradictory characteristic that it is difficult to wind around a reel.

The above characteristics of the polyvinylidene fluoride monofilament of the present invention will be described below with reference to the drawings.

FIG. 1 shows the relationship between diameter and tensile strength of a polyvinylidene fluoride monofilament according to the present invention and a comparative monofilament in Examples described later.

FIG. 2 shows the relationship between the diameter and the knot strength of the polyvinylidene fluoride monofilament according to the present invention and the comparative monofilament in Examples described later.

In FIGS. 1 and 2, the monofilament of the present invention is indicated by ◯, and the comparative monofilament is indicated by ●. The line T in FIG. 1 is TT = in the above formula (I).
-2.0D + 6.1, and the line K in FIG.
KT = -3.0D + 4.8 in I) is shown.

Next, the polyvinylidene fluoride monofilament according to the present invention and the method for producing the same will be described based on Examples. The physical properties of the polyvinylidene fluoride monofilaments obtained in Examples are the values measured by the following measuring methods. is there.

(A) Intrinsic viscosity index ηinh: A sample was dissolved in dimethylformamide at a concentration of 0.4 g / cc and measured at 30 ° C. using an Ostwald viscometer.

(B) Average birefringence (ΔnT): D-line (monochromatic light N
(a lamp) as a light source and determined by a usual Bereck compensator method.

(C) Surface birefringence (ΔnS) of the surface layer portion: by the Becke method, at a measurement temperature of 20 ° C. to 21 ° C., on the fiber surface, the refractive index n1 in the direction perpendicular to the fiber axis and parallel to the fiber The refractive index n2 in the direction is measured, and the difference ΔnS = n1
Defined with -n2.

(D) Tensile strength, knot strength: JIS-L1
According to the definition of 017. That is, the sample is taken in a skein shape and left in a temperature / humidity control room at 20 ° C. and 65% RH for 24 hours, and then “Tensilon” UTM- manufactured by Orientec Co., Ltd.
Using a 4-100 type tensile tester, measurement was performed under the conditions of a test length of 250 mm and a pulling speed of 300 mm / min.

(E) Abrasion resistance: A monofilament loaded with a load of 1/20 × D (fineness) was applied to sandpaper # 3.
180 stainless steel rod with an outer diameter of 50 mm φ covered with 20
The monofilament was moved at a traverse speed of 70 mm / min (traverse width of 35 mm), and the number of revolutions up to cutting was set.

(F) Impact knot strength: Pendulum arm length 281.7 mm, pendulum load 3.72 was set by using a Shimadzu pendulum impact tester with a sample length of 250 mm.
9kg, lifting angle 90 degrees, pulling speed 1.5m / sec
Impact was applied to the monofilament under the conditions of, and the strength at the time of cutting was divided by the fineness to give the value as impact knot strength. In addition, the monofilament cutting strength is DSA6-11 type automatic balance type dynamic strain measuring instrument manufactured by Minebea and Photocoder (2
It was recorded and read the strength at the instant it was cut from the 932 type).

(G) Surface roughness of fiber: DigitalIn
Using a Nanoscope atomic force microscope manufactured by STRENTMENTS INC., the scanning range is 40 μm, the scanning speed is 0.35H.
Z, measured at room temperature in air.

(H) Surface layer compression micro displacement: Using a micro compression tester for Shimadzu powder (PCT-200), pressurizing indenter plane 5
00 μm, load 200 gf, load speed 1.44 gf / s
The displacement value was measured under the condition of ec.

[0096]

Embodiments First, the embodiment of the first invention will be described with reference to Embodiments 1 to 1.
5 and Comparative Examples 1-8.

Example 1 A polyvinylidene fluoride homopolymer chip having an intrinsic viscosity index (ηinh) of 1.2 was supplied to a melt spinning machine and melted at a temperature of 260 ° C. to have a pore size of 1.
The unstretched monofilament was spun out from a 5 mmφ die, passed through a range of an atmosphere length of 150 mm, which was heated to a temperature of 300 ° C. and immediately below the die, and immediately solidified by quenching in a polyethylene glycol solution at a temperature of 20 ° C. Obtained.

The cooled unstretched monofilament was passed through a washing bath composed of water to remove the cooling medium adhering to the surface of the monofilament, and then water droplets on the surface of the monofilament were removed by compressed air and continuously heated to 450 ° C. The high temperature heat treatment was performed for a short time by passing through the air for 1 second.

The surface birefringence of the unstretched monofilament obtained here was 0.2 × 10 ^-3 .

Next, this unstretched monofilament was subjected to 5.8 times pressure heating steam drawing while passing through a pressure chamber filled with pressure heating steam heated at a pressure of 2 Kg / ccm ² G and a temperature of 170 ° C. A 0.24 mm polyvinylidene fluoride monofilament was obtained.

The obtained polyvinylidene fluoride monofilament had an average birefringence (ΔnT) of 37.0 × 10 ⁻³ and a surface birefringence (ΔnS) of 31.8 × 10 ⁻³ . The tensile strength is 5.9 g / d and the knot strength is 4.7.
It was g / d.

Further, the abrasion resistance is 210 times, the impact knot strength is 3.9 g / d, and the surface roughness is the maximum and minimum roughness of 250 n.
m, and the two-dimensional root mean square roughness was 45 nm.

The polymer properties and yarn-forming conditions are shown in Table 1,
The characteristics of the obtained polyvinylidene fluoride monofilament are shown in Table 3.

[Examples 2 to 5 and Comparative Examples 1 to 8] Spinning was carried out in the same process as in Working Example 1, and the polymer properties, spinning conditions and the like were changed as shown in Tables 1 and 2. The physical properties of the obtained monofilaments are shown in Tables 3 and 4.

[0105]

[Table 1]

[0106]

[Table 2]

[0107]

[Table 3]

[0108]

[Table 4]

As is clear from the above results, Example 2
In Examples 4 to 4, the high-temperature short-time heat treatment is performed in a gas state in the undrawn yarn state, and in Example 5, the high-temperature short-time heat treatment is performed in a liquid state in the undrawn yarn state, both of which have the polymer characteristics and the polymer characteristics specified in the present invention. The spinning conditions are satisfied, and all satisfy the structural physical property values of the present invention. As a result, it has excellent tensile strength, knot strength, wear resistance, and impact knot strength, and the fiber surface is very smooth, resulting in good drainability and excellent operability.

On the other hand, as shown in Table 2, Comparative Examples 1 to 8 do not satisfy the specified polymer characteristics and yarn-forming conditions of the present invention, and consequently do not satisfy some or all of the physical properties. This can be seen from the results in Table 4.

For example, in Comparative Example 1, since the high temperature short time heat treatment was not performed, the obtained monofilament had high surface birefringence, low knot strength, and the surface was not smooth.

In Comparative Example 2, since the polymer has a low intrinsic viscosity index, the obtained monofilament has low tensile strength and knot strength.

In Comparative Example 3, since the copolymerization ratio of the polymer is too high, the tensile strength and knot strength of the obtained monofilament are low.

In Comparative Example 4, since the gas temperature under the high-temperature short-time heat treatment condition is low, the obtained monofilament has high surface birefringence and low knot strength.

In Comparative Example 5, the temperature of the high-temperature short-time heat treatment step is too high, and in Comparative Example 6, the high-temperature short-time heat treatment time is too long.

In Comparative Example 7, the yarn diameter is too large to perform uniform cooling, a difference in cooling occurs between the inner and outer layers, the drawability is poor, and the obtained monofilament tensile strength and knot strength are low.

[0117] In Comparative Example 8, even though the heat treatment was carried out at a high temperature for a short time, since the draw ratio in that case was low, the tensile strength and knot strength of the obtained monofilament were low.

Next, the embodiment of the second aspect of the invention will be described as embodiment 6.
8 and Comparative Examples 9 to 16 will be described.

Example 6 Polyvinylidene fluoride homopolymer chips having an intrinsic viscosity index (ηinh) of 1.2 were supplied to a melt spinning machine and melted at a temperature of 260 ° C. to have a pore size of 1.
The unstretched monofilament was spun out from a 5 mmφ die, passed through a range of an atmosphere length of 150 mm, which was heated to a temperature of 300 ° C. and immediately below the die, and immediately solidified by quenching in a polyethylene glycol solution at a temperature of 20 ° C. Obtained.

The cooled unstretched monofilament was passed through a washing bath composed of water to remove the cooling medium adhering to the surface of the monofilament, and then water droplets on the surface of the monofilament were removed with compressed air and continuously heated to 460 ° C. The high temperature heat treatment was performed for a short time by passing through the air for 1 second.

The surface birefringence of the unstretched monofilament obtained here was 0.2 × 10 ^-3 .

Next, this unstretched monofilament was subjected to 5.8 times pressure heating steam drawing while passing through a pressure chamber filled with pressure heating steam heated to a pressure of 2 Kg / cm ² G and a temperature of 170 ° C. A 0.24 mm polyvinylidene fluoride monofilament was obtained.

The obtained polyvinylidene fluoride monofilament had an average birefringence (ΔnT) of 38.0 × 10 ⁻³ , a tensile strength of 5.9 g / d, a knot strength of 4.5 g / d and an abrasion resistance of 210 times. The impact knot strength was 3.9 g / d, and the surface compression minute value was 19.2 μm.

Polymer properties and spinning conditions are shown in Table 5,
The characteristics of the obtained polyvinylidene fluoride monofilament are shown in Table 7.

Example 7 An unstretched monofilament obtained in the same manner as in Example 6 was subjected to a pressure of 2 Kg / cm.
Stretched 4.5 times with ² G, 170 ° C pressurized heated steam, then 1.38 with 170 ° C non-contact heater
By double-drawing twice, a polyvinylidene fluoride monofilament having a diameter of 0.24 mm was obtained.

The average birefringence (ΔnT) of the obtained polyvinylidene fluoride monofilament was 37.7 × 10 ⁻³ ,
The tensile strength was 5.8 g / d, the knot strength was 4.4 g / d, the wear resistance was 210 times, the impact knot strength was 4.0 g / d, and the surface layer compression minute value was 21.0 μm.

The polymer properties and yarn-forming conditions are shown in Table 5,
The characteristics of the obtained polyvinylidene fluoride monofilament are shown in Table 7.

[Example 8 and Comparative Examples 9 to 16] Spinning was carried out in the same process as in Working Example 6 and Working Example 7, and various tests were carried out by changing the polymer properties and spinning conditions as shown in Tables 5 and 6. Was done.

The characteristics of the obtained monofilaments are as shown in Tables 7 and 8.

[0130]

[Table 5]

[0131]

[Table 6]

[0132]

[Table 7]

[0133]

[Table 8]

As is clear from the above results, Examples 6 to 8 satisfying the polymer characteristics and the yarn making conditions specified in the present invention all satisfy the structural physical property values of the present invention and the desired various characteristics. However, the surface of the fiber is smooth and, as a result, it has good drainability and excellent operability.

On the other hand, it can be seen from the results in Table 8 that Comparative Examples 9 to 16 do not satisfy some or all of the physical properties of the monofilament of the present invention.

From the viewpoints of structural parameters and physical properties, for example, Comparative Examples 9 and 10 were not subjected to heat treatment at high temperature for a short time, so that the obtained monofilament had a low value of small displacement in compression, knot strength and abrasion resistance. , And impact knot strength are both low.

Since the polymer used in Comparative Example 11 has a low intrinsic viscosity index, the tensile strength, knot strength, abrasion resistance, impact knot strength, and compressive minute displacement value of the obtained monofilament are all low.

In Comparative Example 12, since the copolymerization ratio of the polymer used was large, the resulting microfilament had a large value of small displacement in compression, and the tensile strength and the knot strength were low.

In Comparative Example 13, since the temperature of the high temperature short time heat treatment condition is low, the obtained monofilament has low knot strength and abrasion resistance.

In Comparative Example 14, since the stretching ratio is too low,
The obtained monofilament has high abrasion resistance and small compression displacement value, but low tensile strength and knot strength.

In Comparative Example 15, the heat treatment temperature at a high temperature for a short time is too high, and the sample is melted and cannot be sampled.

In Comparative Example 16, the high-temperature short-time heat treatment time was too short and the treatment was insufficient, so that the obtained monofilament had low wear resistance and small compression displacement value.

[0143]

INDUSTRIAL APPLICABILITY The polyvinylidene fluoride monofilament of the present invention is excellent in various properties such as tensile strength, knot strength, abrasion resistance, and impact knot strength, so that fishing line, fishing net yarn, glue net yarn, etc. It is suitable as a fishery material.

In particular, the above various excellent properties and transparency,
It is possible to provide a product having improved catchability, operability, and durability by improving water drainage due to properties such as flexibility and smoothness of the fiber surface.

Further, according to the method for producing a polyvinylidene fluoride monofilament characterized by the high temperature short time heat treatment of the present invention, it is possible to efficiently produce a polyvinylidene fluoride monofilament having the above various characteristics.

The polyvinylidene fluoride monofilament of the present invention, taking advantage of its excellent characteristics, is used for applications other than marine products, such as reinforcing materials for rubber belts, transportation materials such as slings and ropes, and fences and rockfall prevention. It can be effectively used for applications such as civil engineering materials.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the diameter (mm) and tensile strength (g / d) of polyvinylidene fluoride monofilaments obtained in Examples of the present invention (including comparison).

FIG. 2 is a graph showing the relationship between the diameter (mm) and the knot strength (g / d) of polyvinylidene fluoride monofilaments obtained in Examples of the present invention (including comparison).

Claims (3)

[Claims] 1. A vinylidene fluoride structural unit accounts for 80% by weight or more, and has an intrinsic viscosity index (ηinh) of 0.8.
A monofilament comprising the above polyvinylidene fluoride polymer, wherein the monofilament has a diameter (D)
Is 0.05 to 0.6 mm and the average birefringence (ΔnT) is 33.
× 10 ^{−3 to} 41 × 10 ⁻³ , the surface birefringence (ΔnS) is 27.
× 10 ^{−3 to} 33 × 10 ⁻³ , the difference (ΔnT−ΔnS) between the average birefringence and the surface birefringence is 3 × 10 ⁻³ or more, the surface maximum / minimum roughness is 400 nm or less, and the two-dimensional root-mean-square roughness is Has a fiber surface structure with a degree of 55 nm or less, and has a tensile strength (T
T) is [−2.0 × D + 6.1] or more (where D is the diameter described above), and the knot strength (KT) is [−3.0 ×].
D + 4.8] or more (where D is the diameter described above), and is a polyvinylidene fluoride monofilament. 2. A vinylidene fluoride constituent unit accounts for 80% by weight or more, and has an intrinsic viscosity index (ηinh) of 0.8.
A monofilament made of the above polyvinylidene fluoride polymer, wherein the monofilament has an average birefringence (ΔnT) of 33 × 10 ^{−3 to} 41 × 10 ⁻³ , an abrasion resistance of 180 to 250 times, and a load. A polyvinylidene fluoride monofilament having a characteristic that the surface layer compression small displacement value at 200 gf is 17 to 25 μm. 3. A vinylidene fluoride structural unit accounts for 80% by weight or more, and has an intrinsic viscosity index (ηinh) of 0.8.
The above polyvinylidene fluoride-based polymer was melt-spun and 2
After cooling and solidifying in an inert liquid at 0 ° C or less, 250 to 5
The surface birefringence (ΔnS) is 1 by performing a high temperature short time heat treatment for 0.1 to 5 seconds in an inert gas at 00 ° C.
A method for producing a polyvinylidene fluoride monofilament, which comprises forming an unstretched monofilament having a size of × 10 ^-3 or less and then stretching the unstretched monofilament under pressure and heating with a draw ratio of 5.6 or more.