JPS60209009A - Production of polyvinylidene fluoride monofilament having high knot strength - Google Patents

Abstract

PURPOSE:To obtain the titled monofilament, having remarkably improved knot strength within a wide range of monofilament diameters, and useful for fishing lines, etc., by melt spinning polyvinylidene fluoride, and drawing the resultant undrawn monofilament at specific temperatures and a specific overall draw into in two stages for specific times of passing through liquid heat medium baths. CONSTITUTION:Polyvinylidene fluoride is melt spun and cooled to prepare an undrawn monofilament, which is first drawn at a temperature (T1) satisfying (Tm-60 deg.C)-Tm [Tm is the melting point ( deg.C) of the polyvinylidene fluoride] at 4.0-6.0 draw ratio (E1) in a liquid heat medium bath in the first stage of two stages and then drawn at a temperature (T2) satisfying (Tm-30 deg.C)-(Tm+ 20 deg.C) in a liquid heat medium bath to a draw ratio (E2) giving >=5.5 overall draw ratio (E1XE2) in the second stage to give the aimed drawn monofilament having 0.05-0.75mm. diameter (D). In the process, the time (t1) of passing through the drawing bath in the first stage and time (t2) of passing through the drawing both in the second stage are controlled under conditions satisfying formulas I and II to afford the above-mentioned aimed monofilament.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for producing polyvinylidene fluoride monofilament which has high knot strength and is particularly suitable for fishing applications such as fishing lines and fishing nets, and various industrial applications.

(Prior art and its problems) Polyvinylidene fluoride monofilament has excellent toughness, impact resistance, transparency, and light resistance.Moreover, it has a high specific gravity (1,8), so it easily sinks in water, and the refractive index of water (1,8). 33
It has a refractive index (1,42) close to ), and has extremely low surface reflection in water, so it is particularly used as a fishing line material.

In general, the physical properties required for fishing line include the above characteristics as well as a balance between tensile strength and knot strength, but conventional polyvinylidene fluoride monofilament has the disadvantage of relatively low knot strength. be. The conventional manufacturing method for polyvinylidene fluoride monofilament involves one or two stages of drawing after melt spinning, and then eight
Method of performing tension heat treatment at 0°C or higher (Special Publication Publication No. 43-13
399 Publication), 2.5 in one stage or multiple stages after melt spinning
Method of stretching and orienting up to 10 times (Japanese Patent Publication No. 44-5359
@Publication) and birefringence heavy chain curve or Young's modulus curve 1
Examples include a method in which primary stretching is performed between a secondary inflection point and a secondary inflection point, followed by secondary stretching (Japanese Patent Publication No. 53-22574), but with these methods, sufficient tensile strength cannot be obtained. However, the knot strength is wire diameter 0.1511+1^
4.2g/dPi! You can only get what you get.

Generally, the knot strength of a monofilament decreases in inverse proportion to its wire diameter, so if the wire diameter is further increased using the conventional method described above, the knot strength will further decrease.

However, recently, the polyvinylidene fluoride monofilament used for fishing lines has become increasingly larger in diameter.
Even with a wire diameter of 0,211+1, the knot strength was reduced to 4.20/
There is a strong demand for the property of having d or more.

(Purpose of the present invention) Therefore, the present inventors investigated the purpose of obtaining polyvinylidene fluoride monofilament with high knot strength over a wide range of diameters, and found that the monofilament after melt spinning was spun in two stages using a liquid heat medium bath. During drawing, by controlling the bath passing time in each drawing step to a specific range corresponding to the diameter of the monofilament to be obtained and the processing temperature, the knot strength can be greatly improved to accommodate a wide range of wire diameters. The present invention was accomplished by discovering that an improved polyvinylidene fluoride monofilament can be obtained.

(Structure of the invention) That is, the present invention melt-spun polyvinylidene fluoride,
In the method of two-stage drawing of an undrawn monofilament obtained by cooling in a liquid medium bath, firstly (Ts - 60°C) to T
l [However, TI is the melting point of polyvinylidene fluoride ('C
)...The same applies hereafter]
T1), one stage stretching was carried out so that the first stage stretching ratio (El) was in the range of 4.0 to 6.0, and then (Ta+-30°C)
By carrying out two-stage stretching at a temperature of 11 (T2) that satisfies ~(TI+20°C) to a second-stage stretching ratio (E2) where the condensation stretching ratio (Et XE2 ) is 5.5 or more, the diameter (D) When obtaining a drawn monofilament having a value of 0.05 to 0.7511, the first drawing bath passing time (tl) and the second drawing bath passing time (t2) are controlled within a range that satisfies the following formula, respectively. The present invention provides a method for producing highly knotted and strong polyvinylidene fluoride monofilament.

11 (seconds) ≧400 D/T 1・・・・・・(1
)t2 (seconds)≦400 D/T2・・・・・・(
2) The polyvinylidene fluoride used in the present invention is a polyvinylidene fluoride homopolymer or copolymer containing 95% by weight or more of a vinylidene fluoride component. Here, copolymerization components that account for less than 5% by weight include tetrafluoroethylene, trifluoromonochloroethylene, trifluoroethylene, monofluoroethylene, hexafluoropropylene, and mixtures thereof. Fluoroethylene and trifluoromonochrome 0
Ethylene is preferred. Also, the vinylidene fluoride component is 95%
Other vinylidene fluoride polymers and/or copolymer polymers may be blended with polyvinylidene fluoride in an amount of % or more by weight. However, the content of vinylidene fluoride component in the polymer or polymer mixture is 955%.
If it is less than % by weight, crystallinity decreases and it becomes difficult to achieve the properties aimed at by the present invention, which is not preferable.

The polyvinylidene fluoride used in the present invention preferably has an intrinsic viscosity index (ηinh) of 0.8 or more, particularly 1.0 or more, as measured with a 0.4s+/cc solution of dimethylformamide, and ηinh is 0.7. In the following cases, sufficient physical properties may not be obtained.

Furthermore, the polyvinylidene fluoride used in the present invention includes, for example, pigments, dyes, light stabilizers, ultraviolet absorbers, antioxidants,
Additives such as crystallization inhibitors and plasticizers can be added during the polymerization process, after the polymerization, or just before spinning, to the extent that they do not inhibit the desired physical properties.

In the present invention, when polyvinylidene fluoride is melt-spun, usual conditions using an extrusion spinning machine can be adopted, such as a polymer temperature of 230-320°C, an extrusion pressure of 10-5ooKt/1OX11 spinning speed of 0.3 ~
A range such as 1001/min and a mouth hole diameter of 0.1 to 3Ill11 can be selected as appropriate.

After passing through a short gas zone, the spun monofilament is cooled in a cooling bath.
Three media include water, glycerin, and liquid compounds inert to polyvinylidene fluoride, such as polyethylene glycol.

The cooled monofilament is sent to the first drawing zone after the cooling medium is removed by a conventional method, and the atmosphere (bath) during drawing and heat setting of the present invention includes, for example, polyethylene glycol, glycerin, and silicone. A heat medium bath in which a liquid medium such as oil is heated is used.

The first-stage stretching conditions of the present invention are such that the stretching ti degree (T1) is (Tg
+-60°C) to Tl, especially at a temperature of (TI-40°C) to T-, the negative stretching ratio (El) is in the range of 4.0 to 6.0, especially 4.3 to 5.0. You need to select a condition. Note that TI in the present invention is the melting point ("C) of polyvinylidene fluoride, and the polymer in chip or bulk form is heated at a rate of temperature increase in a nitrogen atmosphere using a PerkinElmer DT-2B differential scanning calorimeter. Crystal melting peak temperature when measured at 0°C/min (however, if several melting peaks appear together, it means the peak with the highest endothermic peak!F&) ('C).

In the first stage stretching, the stretching temperature (T1) is (Tm-60
℃) is not preferable because fibrillation or whitening occurs in the monofilament.

The upper limit of the first-stage stretching temperature is preferably equal to or lower than the melting point of polyvinylidene fluoride because a liquid heat medium with high thermal efficiency is used as the stretching atmosphere.

In addition, if the first-stage draw ratio (El) is less than 4.0, drawing unevenness will occur and the quality of the yarn will be impaired, and if it exceeds 6.0, it will be difficult to obtain a monofilament with high knot strength, which is undesirable. .

In the present invention, a second stage of drawing is then performed, and the drawing ratio is lowered to 8 to increase the Young's modulus and strength of the monofilament. The second-stage stretching conditions are a stretching temperature (T2) of (Ta-30°C) to 1+20°C), especially (TI-2
At a temperature of 0°C) to Tl, the total stretching ratio (EI
) is 5.5 or more, particularly 5.8 or more. Here T2 is 4t1 more than above
If the total stretching ratio is less than 5.5, the stretching effect will be small and the desired physical properties will not be obtained, which is not preferable.

In addition, in the first-stage stretching and second-stage stretching in the present invention, the above-mentioned stretching a! As long as the stretching ratio (T1 and T2) and the stretching ratio (El and E2) are satisfied, one or both of them can be roughly divided into two or more stages. Further, after the second-stage drawing is completed, the monofilament is preferably passed through a warm water bath in a relaxed state in order to completely remove the additional heating medium and form a more stable fiber structure.

In the present invention, when producing polyvinylidene fluoride monofilament under the above-mentioned drawing conditions, the first-stage drawing bath passing time (tl) and the second-stage drawing bath passing time (T2) are expressed by the above formulas (1) and (2), respectively. It is characterized by controlling the value within a satisfying range, thereby making it possible to obtain a monofilament with further improved knot strength.In the present invention, tl and T2 refer to am at each drawing stage N (process).
It means the IFI (seconds) at the time of passing through the drawing bath, which is brought about by the relationship between the average speed of
and 1-2) and the fact that it has been found that the diameter (D) of the monofilament to be obtained is extremely sensitively reflected in the physical properties and spinnability of the monofilament, which violates the basis of the invention. .

As is clear from equations (1) and 2 above, in the first drawing step, the present invention has the following advantages:
), it is important to control the bath passing time t1 to be relatively long, and further to control the bath passing time t2 to be relatively short in the second drawing stage. Here tl is usually 0
．． The range of 5 seconds to several tens of seconds can be preferably selected, and t2 can be preferably selected within the range of less than 0.5 seconds. However, when tl is smaller than the regulation of the above formula (1) and when t2 is larger than the regulation of the above formula (21), the knot strength of the obtained monofilament decreases, which is not preferable.

(' The difference between tl and t2 is determined by polymer properties, spinning speed,
This can be easily dealt with by changing the drawing speed and/or drawing bath quality according to the temperatures T1, T2 and monofilament diameter (D), etc., thereby further increasing the knot strength of the obtained monofilament. It becomes possible.

(Effects of the present invention) Thus, the polyvinylidene fluoride monofilament obtained by industrially stably spinning by the method of the present invention has a high knot strength of 4.3 Q/d or more even with a wire diameter of 0.2 m + 11, for example. Moreover, it is transparent, has a high Young's modulus, and has excellent tensile properties, so it is particularly useful for fishing applications such as fishing lines and fishing nets as Harris and thread guide, and various industrial applications.

The present invention will be explained in further detail by giving examples below.

In addition, the tensile strength and elongation in the examples and the knot strength and elongation are respectively JIS-L10705.1.1 (standard tensile strength and elongation 1 degree).
and is a value measured according to the measuring method of JIS-L10705.2.1 (standard knot strength and elongation).

Example 1 A polyvinylidene fluoride polymer chip (melting point T-=177°C) having an intrinsic viscosity index (ηinh) of 1.2 at 30°C in a dimethylformamide solution of 0.4g100 was melted at 260°C using an extruder-type spinning machine. After spinning, the spun yarn is immediately passed through a nozzle with a hole diameter of 0.6 m
An undrawn yarn was obtained by cooling in a polyethylene glycol cooling bath at 0°C.

The length of the bath in which this undrawn yarn was heated to 150°C (T1) was 10
Passage time tt-2 in 0 cm polyethylene glycol bath
, 18 seconds, and the first stage stretching was performed so that the stretching ratio E1 was 4.5 times.

Subsequently, it was passed through a polyethylene glycol bath at 160°C (T2) and bath length 5cm+ for a time of t2=.

The stretching ratio E2 is 1.44 while passing in 0.055 seconds.
A second stage of stretching was performed to double the amount.

The total stretching ratio (EI XE2) was 6.5 times.

Next, the drawn yarn was passed through a 95° C. hot water bath at a relaxation ratio of 0.95 and heat-set.

The obtained 1 = monofilament is 110 denier, diameter (
D) = 0.09+++i, and the nodule strength is 4.80/d
,,, knot elongation 18.0%, tensile strength 5.8g/d1
It had excellent properties with a tensile elongation of 23.0%.

Note that the above bath passing time can be regulated by the present invention.
-2.18>400D/T1-0.24・・・・・・
...(1) t2-0.055<400D/T2-0, 225.
(2 Example 2) The same chips as in Example 1 were melted at 280°C using an extruder-type spinning machine, spun through a nozzle with a hole diameter of 2.5 I, and the spun yarn was immediately heated at 20°C. An undrawn yarn was obtained by cooling in a polyethylene glycol cooling bath.

The length of the bath in which this undrawn yarn was heated to 170°C (T1) was 15
Passage time t j in the polyethylene glycol bath of 00-
= 3.00 seconds, the first stage of stretching was performed so that the stretching ratio E1 was 5.0 times.

Subsequently, the film was passed through a polyethylene glycol bath having a bath length of 10 am at 175°C (T2) for 1 hour t2 - 0.103 seconds, and a second stretching was performed so that the stretching ratio E2 was 1.32 times.

The total stretching ratio (EI XE2) was 6.6 times.

Next, the drawn yarn was passed through a 95° C. hot water bath at a relaxation ratio of 0.95 and heat-set.

The monofilament obtained was 498 denier and had a diameter (D
)=0.629111, and the nodule strength is 3.5Q/d.
, knot elongation 17. -0%, tensile strength of 5, Oa/d, and tensile elongation of 22.8%, which had excellent characteristics despite the large diameter.

The bath passing time is compared with the parameters regulated by the present invention as follows.

t1=3.00>400D/T1=1.48...
...(1) t2-0.103<400D/T2-1.44...
(2 Example 3) The same chips as in Example 1 were melted at 270°C using an extruder-type spinning machine, spun through a spinneret with a hole diameter of 1.01 lll, and the spun yarn was immediately soaked in polyethylene glycol at 20°C. An undrawn yarn was obtained by cooling in a cooling bath.

The length of the bath in which this undrawn yarn was heated to 160°C (T1) was 10
Passage time t1-2 in 0cm polyethylene glycol bath
．． The first stage of stretching was performed so that the stretching ratio E1 was 4.5 times while passing the film for 18 seconds.

Next, the film was subjected to a second stretching process, passing through a polyethylene glycol bath at 165°C (T 2 ) and having a bath length of 5 cm for a passing time of t2 - 0.054 seconds, so that the stretching ratio E2 was 1.47 times. Ta.

The total stretching ratio (EI XE2) was 6.6 times.

Next, the drawn yarn was passed through a 95° C. hot water bath at a relaxation ratio of 0.95 and heat-set.

The monofilament obtained was 525 denier and had a diameter (D
)=0.200m5. and knot strength 4.4Q/d,
It had excellent properties for a larger diameter, with a knot elongation of 19.5%, a tensile strength of 5, H1/d, and a tensile elongation of 22.0%.

The bath passing time is compared with the parameters regulated by the present invention as follows.

t1-2.18>400D/T1-0.50...
...(+1 t2-0.054<400D/T2-0.48...
...(2) Examples 4 to 8 and Comparative Examples 1 to 8 0 gold hole diameter to 1. Om-, and the target diameter (D) of the monofilament was set to 0.211, but in the same manner as in Example 1, the yarn was spun, cooled, and the undrawn yarn was taken off, followed by first-stage drawing and second-stage drawing. Monofilaments were produced by varying the conditions for eye drawing as shown in Table 1.

The properties of the obtained monofilament are also shown in Table 1.

As is clear from the results in Table 1, monofilaments with high knot strength can be obtained according to the method of the present invention (Examples 4 to 8); In Examples 1 to 8), only monofilaments with low knot strength could be removed using 6s.

Claims (1)

[Claims] In a method of melt-spinning polyvinylidene fluoride and cooling it to obtain an undrawn monofilament, the undrawn monofilament is drawn in two stages in a liquid medium bath. Showing the melting point ('C) of vinylidene chloride...
・・・・The same applies hereafter] A! The skin (T1) is stretched one step so that the first stretch ratio (El) is in the range of 4.0 to 6.0, and then the film is stretched from -30°C to +20°C).
At a temperature (T2) that satisfies
> is 5.5 or more by performing two-stage stretching to a second-stage stretching ratio (E2) of 5.5 or more, so that the diameter (D) is 0.05 to 0.
When obtaining a 75 mm stretched monofilament, the first drawing bath passing time (tl) and the second drawing bath passing time (
tl) within a range that satisfies the following formulas. 11 (seconds)≧400D/T1...(1)t2
(Seconds) ≦4000/T2 (2)