阅读说明：本技术 一种渔用聚偏二氟乙烯单丝的制备方法 (Preparation method of fishing polyvinylidene fluoride monofilament ) 是由 闵明华 王鲁民 张勋 刘永利 于 2021-01-13 设计创作，主要内容包括：本发明涉及一种渔用聚偏二氟乙烯单丝的制备方法,包括：切片干燥、加热熔融、纺丝和拉伸。本发明通过独特的熔融纺丝和拉伸工艺制备得到渔用聚偏二氟乙烯单丝,具有不吸水、比重大、切水快、阻力大、钓力大、抗老化、寿命长的特性,可用于制造流刺网、钓鱼丝、网袋、缆绳、远洋拖网等。(The invention relates to a preparation method of fishing polyvinylidene fluoride monofilament, which comprises the following steps: drying the slices, heating and melting, spinning and stretching. The fishing polyvinylidene fluoride monofilament prepared by the unique melt spinning and drawing process has the characteristics of no water absorption, large specific gravity, quick water cutting, large resistance, large fishing force, ageing resistance and long service life, and can be used for manufacturing spunlaced nets, fishing threads, net bags, cables, ocean trawls and the like.)

1. A preparation method of fishing polyvinylidene fluoride monofilament comprises the following steps:

(1) slicing and drying polyvinylidene fluoride, heating and melting the polyvinylidene fluoride by a screw extruder, metering the polyvinylidene fluoride by a metering pump, and melting and extruding the polyvinylidene fluoride by a spinneret plate; wherein the heating and melting temperature is set as follows: the feeding area is 120 ℃, the melting area is 170-185 ℃, the compression area is 180-195 ℃ and the metering area is 185-200 ℃;

(2) then, spinning in a spinning box, cooling the obtained monofilament by cold water, and performing four-stage hot stretching to obtain fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3-4 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 2-3 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1-2 times, and the stretching temperature is 110-120 ℃; the four-stage stretching multiple is 0.98-1.2 times, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

2. The method of claim 1, wherein: the number average molecular weight of the polyvinylidene fluoride in the step (1) is 150000-180000.

3. The method of claim 1, wherein: the drying process in the step (1) specifically comprises the following steps: drying for 24-36 hours at the temperature of 70-120 ℃ and the vacuum degree of-0.05-0.1 MPa.

4. The method of claim 1, wherein: the spinning process in the step (2) is specifically as follows: the temperature of the spinning box body is 170-200 ℃, and the spinning speed is 5-50 m/min.

5. The method of claim 1, wherein: the fishing polyvinylidene fluoride monofilament in the step (2) is used for manufacturing a spunlace net, a fishing line, a net bag, a cable or an ocean trawl.

Technical Field

The invention belongs to the field of fishing lines, and particularly relates to a preparation method of fishing polyvinylidene fluoride monofilament.

Background

With the rapid development of the economic and scientific levels, the living standard and the living quality of people are continuously improved, and the modern leisure fishery, especially the leisure fishing, relieves the pressure of people and relaxes the mind and body of people, and brings a new life for the development of fishing ports in fishing villages. However, as an important auxiliary tool for leisure fishing, research and development of fishing lines are still in the beginning stage in China. Currently, fishing lines are mainly made of nylon, and the manufacturing process is generally that polyamide 6, polyamide 66 or a mixture of the two polymers is melt-spun, and then post-processed, such as setting, dyeing and the like. The nylon wire has the characteristics of good ductility and elasticity, but the knotting strength of the nylon wire is low, the refractive index of the nylon wire is far greater than that of water, in addition, the nylon wire has low initial modulus and is easy to stretch, so that the signal transmission of the fish-biting hook is untimely and unclear, and in addition, the nylon wire is easy to absorb water, so that the signal transmission of the fish-biting hook is greatly attenuated.

Polyvinylidene fluoride (PVDF for short), namely Poly (vinylidene fluoride), can be used for manufacturing professional fishing monofilaments to replace the traditional nylon monofilaments. The polyvinylidene fluoride monofilament has the characteristics of no water absorption, high strength, ageing resistance and long service life, has a hard surface, is more resistant to sharp fish teeth abrasion, has lower optical density than nylon, and makes a fishing line less prone to be found by sharp fish eyes. At the same time, the density of the fishing line is higher than that of nylon, so that the fishing line can sink towards the fish more quickly. When the fishing of carnivorous attack fishes, the polyvinylidene fluoride monofilament often becomes the first lead wire, and the use position of the polyvinylidene fluoride fishing line cannot be affected due to sharp obstacles such as reef and the like in sea fishing.

However, at present, the preparation process of the polyvinylidene fluoride fishing line is still complex, and further market application of the fishing line is limited.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of fishing polyvinylidene fluoride monofilament, which is prepared by a unique melt spinning and drawing process, has the characteristics of no water absorption, large specific gravity, quick water cutting, large resistance, large fishing force, ageing resistance and long service life, and can be used for manufacturing spunlaced nets, fishing threads, net bags, cables, ocean trawls and the like.

The invention provides a preparation method of fishing polyvinylidene fluoride monofilament, which comprises the following steps:

(1) slicing and drying polyvinylidene fluoride, heating and melting the polyvinylidene fluoride by a screw extruder, metering the polyvinylidene fluoride by a metering pump, and melting and extruding the polyvinylidene fluoride by a spinneret plate; wherein the heating and melting temperature is set as follows: the feeding area is 120 ℃, the melting area is 170-185 ℃, the compression area is 180-195 ℃ and the metering area is 185-200 ℃;

(2) then, spinning in a spinning box, cooling the obtained monofilament by cold water, and performing four-stage hot stretching to obtain fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3-4 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 2-3 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1-2 times, and the stretching temperature is 110-120 ℃; the four-stage stretching multiple is 0.98-1.2 times, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

The number average molecular weight of the polyvinylidene fluoride in the step (1) is 150000-180000.

The drying process in the step (1) specifically comprises the following steps: drying for 24-36 hours at the temperature of 70-120 ℃ and the vacuum degree of-0.05-0.1 MPa.

The spinning process in the step (2) is specifically as follows: the temperature of the spinning box body is 170-200 ℃, and the spinning speed is 5-50 m/min.

The fishing polyvinylidene fluoride monofilament in the step (2) is used for manufacturing a spunlace net, a fishing line, a net bag, a cable or an ocean trawl.

Advantageous effects

The fishing polyvinylidene fluoride monofilament prepared by the unique melt spinning and drawing process has the characteristics of no water absorption, large specific gravity, quick water cutting, large resistance, large fishing force, ageing resistance and long service life, and can be used for manufacturing spunlaced nets, fishing threads, net bags, cables, ocean trawls and the like.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

Polyvinylidene fluoride slices with the number average molecular weight of 150000 are selected and dried for 24 hours at the temperature of 70 ℃ and the vacuum degree of-0.05 MPa. Heating and melting polyvinylidene fluoride slices by a screw extruder, metering by a metering pump, and then melt-extruding by a spinneret plate, wherein the screw melt-spinning temperature is as follows: a feeding zone is 120 ℃, a melting zone is 170 ℃, a compression zone is 170 ℃, and a metering zone is 170 ℃; the temperature of the spinning box body is 170 ℃; the spinning speed is 5 m/min; cooling the obtained monofilament by cold water, and then carrying out four-stage hot stretching to obtain a fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 2 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1 time, and the stretching temperature is 110-120 ℃; the four-stage stretching multiple is 0.98 times, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

Example 2

Polyvinylidene fluoride slices with the number average molecular weight of 160000 are selected and dried for 36 hours under the conditions of the temperature of 80 ℃ and the vacuum degree of-0.05 MPa. Heating and melting polyvinylidene fluoride slices by a screw extruder, metering by a metering pump, and then melt-extruding by a spinneret plate, wherein the screw melt-spinning temperature is as follows: a feeding zone of 120 ℃, a melting zone of 170 ℃, a compression zone of 175 ℃ and a metering zone of 175 ℃; the spinning box temperature is 175 ℃; the spinning speed is 10 m/min; cooling the obtained monofilament by cold water, and then carrying out four-stage hot stretching to obtain a fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 2 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1 time, and the stretching temperature is 110-120 ℃; the four-stage stretching multiple is 1 time, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

Example 3

Polyvinylidene fluoride slices with the number average molecular weight of 170000 are selected and dried for 36 hours at the temperature of 90 ℃ and the vacuum degree of-0.05 MPa. Heating and melting polyvinylidene fluoride slices by a screw extruder, metering by a metering pump, and then melt-extruding by a spinneret plate, wherein the screw melt-spinning temperature is as follows: a feeding zone with the temperature of 120 ℃, a melting zone with the temperature of 175 ℃, a compression zone with the temperature of 175 ℃ and a metering zone with the temperature of 180 ℃; the temperature of the spinning box body is 180 ℃; the spinning speed is 25 m/min; cooling the obtained monofilament by cold water, and then carrying out four-stage hot stretching to obtain a fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 3 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1.5 times, and the stretching temperature is 115-120 ℃; the four-stage stretching multiple is 0.98 times, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

Example 4

Selecting polyvinylidene fluoride slices with the number average molecular weight of 180000, and drying for 24 hours at the temperature of 100 ℃ and the vacuum degree of-0.1 MPa. Heating and melting polyvinylidene fluoride slices by a screw extruder, metering by a metering pump, and then melt-extruding by a spinneret plate, wherein the screw melt-spinning temperature is as follows: a feeding zone, a melting zone, 175 ℃, a compression zone, 180 ℃ and a metering zone, wherein the feeding zone is 120 ℃, the melting zone is 175 ℃, the compression zone is 180 ℃, and the metering zone is 185 ℃; the temperature of the spinning box body is 190 ℃; the spinning speed is 30 m/min; cooling the obtained monofilament by cold water, and then carrying out four-stage hot stretching to obtain a fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3.5 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 2.6 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1.2 times, and the stretching temperature is 110-120 ℃; the four-stage stretching multiple is 1.2 times, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

Example 5

Selecting polyvinylidene fluoride slices with the number average molecular weight of 180000, and drying for 24 hours at the temperature of 120 ℃ and the vacuum degree of-0.1 MPa. Heating and melting polyvinylidene fluoride slices by a screw extruder, metering by a metering pump, and then melt-extruding by a spinneret plate, wherein the screw melt-spinning temperature is as follows: a feeding zone is 120 ℃, a melting zone is 180 ℃, a compression zone is 180 ℃, and a metering zone is 185 ℃; the temperature of the spinning manifold is 200 ℃; the spinning speed is 50 m/min; cooling the obtained monofilament by cold water, and then carrying out four-stage hot stretching to obtain a fishing polyvinylidene fluoride monofilament; wherein, the four-stage hot stretching process comprises the following steps: the primary stretching multiple is 3 times, and the stretching temperature is 80-90 ℃; the secondary stretching multiple is 2.8 times, and the stretching temperature is 90-100 ℃; the third-stage stretching multiple is 1.6 times, and the stretching temperature is 110-120 ℃; the four-stage stretching multiple is 1.0 time, and the stretching temperature is 130-160 ℃; the stretching medium is hot water bath or hot air bath.

Comparative example 1

Other conditions were as in example 5, except that: drying at 60 deg.C and vacuum degree of-0.2 MPa for 24 hr.

Comparative example 2

Other conditions were as in example 5, except that: the feed zone temperature was 150 ℃.

Comparative example 3

Other conditions were as in example 5, except that: four-stage hot stretching is not carried out, the total stretching multiple is 8 times, the stretching medium is a hot water bath, and the stretching temperature is 100 ℃.

The mechanical property test method refers to aquatic industry standard SC/T5005-2014 fishing polyethylene monofilaments, and the detection data of the embodiment and the comparative example are shown in Table 1:

TABLE 1 examination data of examples and comparative examples

	Breaking strength (cN/dtex)	Knot strength (cN/dtex)
			Example 1	6.0	4.6
Example 2	7.1	5.0
			Example 3	7.8	4.9
Example 4	7.2	5.0
			Example 5	7.5	5.5
Comparative example 1	5.8	4.4
			Comparative example 2	5.5	4.2
Comparative example 3	6.2	4.6

Comparative example 1 the temperature and pressure of vacuum drying are different from those of example 5, the temperature and pressure of the drying process determine the water content of the polyvinylidene fluoride chips, and the presence of water degrades the polyvinylidene fluoride chips during the heating melt spinning process, thus affecting the breaking strength and the knot strength of the final monofilament. Comparative example 2 the temperature of the feed zone was 150 c, unlike polylactic acid or PHBV, a higher feed temperature would cause a certain degree of thermal degradation of the polyvinylidene fluoride, resulting in slower cooling of the polyvinylidene fluoride after redrawing and less than perfect crystallization, directly affecting the breaking strength and nodule strength. Comparative example 3, which did not employ the four-stage drawing process but directly drawn, resulted in insufficient degree of orientation of the polyvinylidene fluoride macromolecular chains during drawing, thereby directly affecting the fracture strength and the nodule strength.