JPS60215810A - Polyvinylidene fluoride monofilament and its production - Google Patents

Abstract

PURPOSE:Undrawn monofilaments of polyvinylidene fluoride are subjected to the first-stage drawing, rapidly cooled down in a liquid lower than a specific temperature, then the second-stage and later drawings are effected to produce the titled filaments which have a long cycle of less than a specific value and high knot strength. CONSTITUTION:A polyvinylidene fluoride polymer is melt-extruded and the undrawn monofilaments are subjected to multistage drawing where, after the first-stage drawing, the monofilaments are rapidly cooled down with a liquid such as water or ethylene glycol of more than 80 deg.C, preferably more than 90 deg.C lower than the drawing temperature. Then, the second-stage and later drawings are effected to give the objective monofilaments having a long cycle of less than 190Angstrom .

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to polyvinylidene fluoride (pvo
It is called p. ) type monofilament and its manufacturing method.

(Conventional technology) Pv leaf has a high specific gravity and a refractive index close to that of water, making it visible underwater.It has low water absorption and low surface tension, so it repels water well, has excellent weather resistance, and its bending Young's modulus is low. Due to its moderate properties, it is suitable as monofilament for fishing lines and fishing nets (see Japanese Patent Publication No. 5359/1983), and has been commercialized. However, the knot strength is lower than that of nylon monofilament, which limits its use.

For this reason, many studies have been made to obtain Pv monofilaments with high knot strength.

For example, Japanese Patent Publication No. 51-32667 states that it is effective to include polymethyl methacrylate, but this has not yet reached a satisfactory level.

(Objective of the Invention) The object of the present invention is to provide a Pv lobe-based seven filament with high knot strength and a method for producing the same.

(Structure of the Invention) As a result of various studies to achieve the above object, the present inventors found that among the factors that determine the fine structure of a monofilament,
The size of the long period greatly affects the knot strength, and while conventional monofilament has a long period of about 200, the nodule strength is significantly improved by having a long period of 19oA or less. In addition, such long-period short monofilaments are drawn in multiple stages.
It has been found that this can be easily obtained by rapid cooling treatment after the first stage stretching.

The present invention was made based on such knowledge, and the gist thereof is as follows.

(Pvl monofilament with a long period of 11t9oa or less.

(21 In a method for producing a Pv leaf monofilament by melt-spinning a PV leaf-based polymer into an undrawn monofilament and stretching it in multiple stages, after the first stage drawing, a liquid at a temperature of 80°C or more lower than the drawing temperature is used. A method for producing Pv leaf monofilament characterized by rapid cooling inside.

In the present invention, the long period is measured from the small-angle X-ray scattering pattern, and the long period is measured from the small-angle X-ray scattering pattern.
The distance between them is l, the maximum width of the upper and lower scattered lights with the equatorial plane as the axis of symmetry is 2a, and the wavelength of the CuKα ray is λ (= 1.5418
When + tan 2d = a/1, the long period is expressed as λ/2sind.

In the present invention, in addition to the Pv leaf homopolymer, vinylidene fluoride is used as the main component (preferably 8
5% by weight or more), and tetrafluoroethylene,
Monochlorotrifluoroethylene.

A Pv leaf copolymer containing vinyl fluoride, hexafluoropropylene, perfluoroisopropoxyethylene, etc. as a copolymer component is used, and a mixture of two or more types of polymers may be used.

And in order to demonstrate sufficient strength characteristics.

Intrinsic viscosity (measured in dimethylformamide at 30°C)
is 0.9 or more, preferably 1.0 or more.

The monofilament of the present invention needs to have a long period of 190 Å or less, and particularly preferably has a long period of xeoi or less. If the long period is long.

It is thought that the nodule strength does not increase because the number of microstructural units for dispersing stress decreases when a large complex deformation such as a nodule occurs.

The monofilament of the present invention can be produced by a conventional method, except that after the first stage drawing, the monofilament is rapidly cooled in a liquid at a temperature lower than the drawing temperature by 80° C. or more, preferably by 90° C. or more. That is, Pν leaf-based polymer is 23
Melt-spun at 0-300°C, cooled and solidified in an inert liquid such as water at 50°C or less, and in a liquid or gas bath at 100-175°C.

After performing the first stage stretching of about 3 to 5 times and quenching.

This is a method in which the second and subsequent stages of stretching are performed in a gas bath at 130 to 200°C or in a liquid bath at 130 to 175°C so that the total stretching ratio is 6 to 8 times, and further heat treatment is performed as necessary. .

The rapid cooling after the first stage stretching is performed using an inert liquid such as water, ethylene glycol, or glycerin, and the temperature is 80°C or more lower than the temperature after the first stage stretching.
This is necessary in order to obtain a monofilament with a long period of 11 or less.

Note that the monofilament of the present invention contains a plasticizer.

It goes without saying that the heat stabilizer 1 may contain additives such as colorants and antioxidants.

The monofilament of the present invention has excellent strength characteristics and can be used not only as fishing materials such as fishing lines and fishing nets, but also as filter cloths, brushes, etc.

(Examples) Hereinafter, the present invention will be explained in more detail with reference to Examples. The intrinsic viscosity is a value measured in dimethylformamide at 30°C, and the wet knot strength is a value measured according to the JISL 1013 method.

Examples and Comparative Examples A Pv leaf with an intrinsic viscosity of 1.21 was spun using an extruder-type melt spinning machine at a temperature of 280°C, and the undrawn monofilament was cooled in a 30°C water bath, and then in a glycerin bath at 11°C. First stage stretching was carried out at a stretching ratio of 3.5 times, and then quenched in a 12°C water bath, followed by second stage stretching at a stretching ratio of 1.8 to 2.0 times in a gas atmosphere at T3°C. , a monofilament of approximately 500 denier was obtained (spin-drying method).

Table 1 shows the relationship between each temperature during the above-mentioned stretching and the long period and wet knot strength of the obtained monofilament.

Table 1 (Effects of the Invention) As mentioned above, the present invention provides Pv with excellent wet knot strength.
The present invention provides a heptanofilament of type I and a method for producing the same.

Claims (1)

Scope of Claims: (Polyvinylidene fluoride monofilament having a long period of 111905 or less. A method for producing polyvinylidene fluoride monofilaments, which comprises, after the first stage drawing, quenching in a liquid at a temperature 80° C. or more lower than the drawing temperature.