KR101235255B1 - Manufacturing method of high strength polyethylene multifilament drawn fibers containing nano silica particles - Google Patents

Abstract

The present invention relates to a method for producing a high strength polyethylene multifilament drawn yarn containing nano silica particles, (S1) based on 100 parts by weight of polyethylene pellets having a crystallinity of 60 to 65% and nano silica particles having an average particle diameter of 5 to 30 nm. To prepare a polyethylene-nano silica particles masterbatch by mixing to 0.01 to 0.3 parts by weight; (S2) The polyethylene-nano silica particle masterbatch is put into an extruder having a temperature of 260 to 280 ° C. to melt polyethylene, and then passed through a spinneret having a temperature of 280 to 300 ° C. to contain polyethylene nanoparticles. Preparing a multifilament; (S3) simultaneously cooling the polyethylene multifilament containing the nano-silica particles by 300 to 400 times while preparing a non-drawn yarn having a crystallinity of 40 to 50%; And (S4) stretching the unstretched yarn 18 times or more while passing the heating chamber having a temperature of 100 to 120 ° C. to produce polyethylene multifilament drawn yarn having a crystallinity of 80% or more.
By controlling the size and content of the nano-silica particles and the process conditions according to the present invention, it is possible to produce a high strength polyethylene multifilament drawn yarn.

Description

MANUFACTURING METHOD OF HIGH STRENGTH POLYETHYLENE MULTIFILAMENT DRAWN FIBERS CONTAINING NANO SILICA PARTICLES}

The present invention relates to a method for producing high strength polyethylene multifilament drawn yarn containing nano silica particles, which can be used for various purposes such as safety gloves, protective clothing, protective clothing, industrial ropes, aquaculture nets, geotextiles, work nets and the like.

High-performance textiles such as industrial or civilian ropes, farmed fishing nets, safety gloves, protective clothing, and sword suits, polyethylene multifilament yarns having high strength are used for geotextiles and work nets in civil engineering and construction.

As a method for producing a high strength polyethylene multifilament drawn yarn, a method using an ultra high molecular weight polyethylene resin having a molecular weight of 4 million or more is well known. Ultra high molecular weight polyethylene resins cannot be melt-extruded due to their high molecular weight. Therefore, in one step gelling the ultra-high molecular weight polyethylene resin to a large amount of oil and spinning with spinneret of the extruder to produce a non-drawn yarn, and then in two steps to replace the oil in the undrawn yarn containing a large amount of oil, Polyethylene multifilament drawn yarns are prepared. However, this method has a disadvantage in that the manufacturing process is complicated and the manufacturing cost is high because the solvent must be used and treated.

Another method for producing a high strength polyethylene multifilament drawn yarn is a method of stretching a non-drawn yarn obtained after melt spinning a polyethylene resin to obtain a high strength polyethylene multifilament drawn yarn.

For example, Korean Laid-Open Patent Publication No. 1989-0004001 improves the uniformity between spinning filaments by preventing cyclic or continuous melt fracture phenomena and sharkskin phenomena caused by viscoelastic intrinsic properties during melt extrusion of high density polyethylene resins. A method of obtaining high strength polyethylene multifilament drawn yarns after stretching is disclosed. In addition, Korean Patent Publication No. 2009-0049099 discloses a weight average molecular weight of 300,000 or less, a ratio of weight average molecular weight to number average molecular weight (Mw / Mn) of 3.0 or less and 5 or more carbon atoms produced using a metallocene catalyst. A method for producing a high strength polyethylene multifilament drawn yarn is disclosed by melt extruding a polyethylene resin having a branched chain of 0.01 to 3.0 per 1000 carbons of a main chain and then stretching.

However, when melt spinning the polyethylene resin, the molecular chain entanglement in the resin is very high and the crystallization rate is high. That is, since the crystallization proceeds rapidly when the polyethylene resin melted through the spinneret is cooled to take out the undrawn yarn, an undrawn yarn having a high degree of crystallinity is obtained. Thereby, since it is difficult to extend | stretch unstretched yarn with a high draw ratio, there exists a limit in obtaining high strength polyethylene multifilament stretched yarn.

The present invention has been made to solve the above problems, to provide a method for manufacturing a high-strength polyethylene multifilament drawn yarn by controlling the size and content of nano silica particles and process conditions.

In order to achieve the above object, the manufacturing method of high-strength polyethylene multifilament drawn yarn containing nano silica particles according to the present invention,

(S1) preparing a polyethylene-nano silica particle masterbatch by mixing polyethylene pellets having a crystallinity of 60 to 65% and nano silica particles having an average particle diameter of 5 to 30 nm at 0.01 to 0.3 parts by weight based on 100 parts by weight of polyethylene;

(S2) The polyethylene-nano silica particle masterbatch is put into an extruder having a temperature of 260 to 280 ° C. to melt polyethylene, and then passed through a spinneret having a temperature of 280 to 300 ° C. to contain polyethylene nanoparticles. Preparing a multifilament;

(S3) simultaneously cooling the polyethylene multifilament containing the nano-silica particles by 300 to 400 times while preparing a non-drawn yarn having a crystallinity of 40 to 50%; And

(S4) stretching the unstretched yarn 18 times or more while passing the heating chamber having a temperature of 100 to 120 ℃ to prepare a polyethylene multifilament stretched yarn having a crystallinity of 80% or more.

In the method for producing polyethylene fiber according to the present invention, when preparing a polyethylene-nano silica particle masterbatch according to the step (S1), it is preferable to prepare a polyethylene-nano silica particle masterbatch by adding a compatibilizer. . Such compatibilizers include styrene-ethylene-butylene-styrene (SEBS) copolymer or maleic anhydride-grafted polypropylene (MAN-g-PP) alone. Or these can be mixed and used.

In addition, in the method for producing polyethylene fiber according to the present invention, it is preferable that the nano silica particles use those whose surface is modified with a surfactant. As such a surfactant, it is more preferable to use the cationic surfactant which consists of a quaternary ammonium salt.

According to the present invention, silica particles of a predetermined size and content contained in the polyethylene-nano silica particle masterbatch delay the crystallization rate of the undrawn yarn in the cooling process after melt spinning, thereby obtaining undrawn yarn having low crystallinity. In addition, by optimally designing conditions such as the degree of crystallinity and melting and spinning temperature of the polyethylene resin, it is possible to produce a high-strength polyethylene multifilament drawn yarn while ensuring fairness.

Hereinafter, the present invention will be described in detail. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Hereinafter, a method for producing polyethylene fiber according to the present invention will be described in detail.

First, a polyethylene-nano silica particle masterbatch is prepared by mixing polyethylene pellets having a crystallinity of 60 to 65% and nano silica particles having an average particle diameter of 5 to 30 nm at 0.01 to 0.3 parts by weight based on 100 parts by weight of polyethylene (S1 step). . As a method of preparing the masterbatch, any method capable of sufficiently dispersing the nano silica particles in the polyethylene resin may be used. For example, silica particles and polyethylene pellets may be added to a twin screw extruder, mixed, and then prepared as pellet-type polyethylene-nano silica particle master batches.

Unlike the ultra high molecular weight polyethylene, any polyethylene can be used as long as it has a molecular weight capable of melt spinning. For example, a polyethylene resin having a melt index of 0.5 to 1.5 g / 10 min may be used. As a kind of polyethylene, it is preferable to use a high density polyethylene manufactured using a Ziegler-Natta catalyst or a metallocene catalyst, but is not limited thereto. Polyethylene pellets are made of polyethylene resin having a crystallinity of 60 to 65%. If the degree of crystallinity is less than 60%, it is difficult to express high strength, and if it is 65% or more, it is difficult to produce undrawn yarn having a crystallinity of 40 to 50% in the draft and cooling steps described later, and as a result, it is impossible to produce a high strength polyethylene multifilament drawn yarn. do.

The average particle diameter of the silica particles added to prepare the polyethylene-nano silica particle masterbatch is 5 to 30 nm. If the average particle diameter of the silica particles is less than 5 nm or more than 30 nm, the strength of the finally obtained polyethylene multifilament drawn yarn is lowered. As the silica particles, silica particles made of amorphous silicon dioxide obtained by combustion of an organic silicon compound are preferable, but are commercially available from Degussa, Germany under a product name such as Aerosil. The content of the silica particles is 0.01 to 0.3 parts by weight based on 100 parts by weight of polyethylene resin. When the content of the silica particles is less than 0.01 parts by weight, the effect of the addition of the silica particles is hardly exhibited, and when the content of the silica particles is more than 0.3 parts by weight, the dispersibility of the silica particles is lowered, and the strength of the polyethylene multifilament drawn yarn is lowered.

In the method for producing polyethylene fiber according to the present invention, when preparing the polyethylene-nano silica particle masterbatch according to the step (S1), it is preferable to add a compatibilizer to improve the dispersibility of the nano silica particles. Such compatibilizers include styrene-ethylene-butylene-styrene (SEBS) copolymer or maleic anhydride-grafted polypropylene (MAN-g-PP) alone. Or these can be mixed and used. In particular, MAN-g-PP is more preferable because the maleic anhydride is grafted on the surface to improve the adhesion between the inorganic material having an -NH ₂ group and the olefinic polymer. The preferred content of the compatibilizer is 0.1 to 3.0 parts by weight based on 100 parts by weight of polyethylene resin.

In addition, in the method for producing polyethylene fiber according to the present invention, it is preferable that the nano silica particles use those whose surface is modified with a surfactant. The dispersibility of the silica particles is improved by the surfactant, and in particular, the dispersibility may be further improved by interaction with the compatibilizer. As such a surfactant, all of an ionic surfactant, a nonionic surfactant, an amphoteric surfactant, etc. can be used, but it is more preferable to use the cationic surfactant which consists of quaternary ammonium salts especially. Such quaternary ammonium salts include alkyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride, alkyldimethylmetharylammonium chloride and the like. The preferred content of the surfactant is 45 to 55 parts by weight based on 100 parts by weight of the silica particles.

Subsequently, the prepared polyethylene-nano silica particle masterbatch is placed in an extruder having a temperature of 260 to 280 ° C. to melt polyethylene, and then passed through a spinneret having a temperature of 280 to 300 ° C. to contain polyethylene nanoparticles. To prepare a multifilament (step S2).

When the temperature of the extruder is lower than 260 ° C., the polyethylene is not sufficiently melted and spinning is difficult. When the temperature of the extruder is higher than 280 ° C., the melt viscosity of the polyethylene is lowered, so that high strength is difficult to be expressed and it is difficult to wind more than a certain speed. The result of completely melting the polyethylene is passed through a spinneret heated to a temperature of 280 ~ 300 ℃ using a gear pump to produce a polyethylene multifilament containing nano silica particles. If the temperature of the spinneret is lower than 280 ° C, the spinning workability is not good. If the temperature of the spinneret is higher than 300 ° C, thermal decomposition of polyethylene occurs, so that it is impossible to manufacture high-strength polyethylene multifilament by increasing the draw ratio.

Thus, the multi-filament containing the nano-silica particles passed through the spinneret is simultaneously cooled while being drafted at 300 to 400 times to prepare undrawn yarn having a crystallinity of 40 to 50% (step S3).

If the draft ratio is lower than 300 times, the crystallinity of the undrawn yarn is less than 40%, so the crystallinity is too low, and even if it is drawn at a high magnification, it is difficult to express high strength. In addition, when it is higher than 400 times, the crystallinity of the non-drawn yarn is increased to 50% or more due to the increase of the crystallinity due to the stress increase. Accordingly, it is not possible to increase the elongation in the stretching step described later, it is not possible to produce a high strength polyethylene multifilament.

Then, the unstretched yarn is stretched 18 times or more while passing through a heating chamber having a temperature of 100 to 120 ° C. to prepare polyethylene multifilament stretched yarn having a crystallinity of 80% or more (step S4).

When the temperature of the heating chamber is lower than 100 ° C., the polyethylene chain may not have enough energy to move, and thus it may not be stretched more than 18 times, thereby making it impossible to manufacture high strength fibers. In addition, when the temperature of the heating chamber is higher than 120 ° C, breakage or refolding of the chain occurs at the time of stretching and high strength fibers cannot be produced.

Polyethylene multifilament prepared by the above-described method was obtained by shrinking in a high speed roller and then wound in a winder to obtain polyethylene multifilament having a crystallinity of 80% or more.

The polyethylene multifilament according to the present invention has a monofilament fineness of 1 to 2 deniers and an aggregate of 200 to 400 monofilament number. If the monofilament fineness is less than 1 denier, the occurrence of wool is serious and the quality of the yarn is lowered. In addition, when the number of monofilaments is less than 200, high strength fibers cannot be manufactured. When the number of monofilaments is more than 400, uniform cooling is not achieved, and thus the stretchability of the undrawn yarn is inferior.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

Crystallinity

The degree of crystallinity was calculated by the following formula based on the weight fraction from the density (ρ) of the sample, wherein the density values of the crystal and amorphous were 1.000 g / cm ³ and 0.855 g / cm ³ , respectively.

Where X _c is the crystallinity, ρ is the density of the sample, ρ _c is the density of the crystal region, and ρ _a is the density of the amorphous region.

Strength and elongation: ASTM  D 2256

Strength and elongation were measured at a tensile speed of 200 mm / min using an elongation tester (Instron 5567).

The half-crystallization time (t _1/2)

The pellet samples used in the following Examples and Comparative Examples were completely melted at 160 ° C. for 10 minutes, and then measured by rapidly lowering the temperature to the respective semicrystallization temperatures (105 ° C., 110 ° C., and 115 ° C.).

Example  One

After dissolving 9 g of cationic surfactant oleyldimethylbenzylammonium chloride in 25 g of caustic soda solution and 193.1 g of distilled water, 19.25 g of silica having an average particle diameter of 7 nm was added to the solution and stirred for 3 hours, followed by 80 ° C. deionized water. After washing to remove excess surfactant, it was dried at room temperature to prepare silica particles whose surface was modified with a surfactant.

Polyethylene-nano silica particles masterbatch by adding 100 parts by weight of polyethylene pellets having a crystallinity of 62%, 0.05 parts by weight of surface-modified silica particles and 0.5 parts by weight of compatibilizer (MAN-g-PP) prepared by the above-described method in a twin screw extruder. Was prepared.

Subsequently, the polyethylene-nano silica particle masterbatch was put into an extruder having a temperature of 280 ° C., melted, spun through a spinneret having a temperature of 290 ° C. using a gear pump, and cooled and wound while drafting at 350 times to obtain a crystallinity of 45%. Phosphorous undrawn yarn was prepared. The unstretched yarn was stretched 22 times while passing through a heating chamber at 110 ° C. to produce polyethylene multifilament having a crystallinity of 81.3%.

Example  2 ~ 3

The same process as in Example 1 was carried out except that the content of silica was changed to the content shown in Table 1.

Example  4 to 6

The same procedure as in Example 1 was conducted except that the size of the silica particles was changed to the size shown in Table 1.

Example  7-8

It carried out similarly to Example 1 except having changed the draft ratio in the ratio of Table 1.

Comparative example  1-3

The same process as in Example 1 was carried out except that the content of silica was changed to the content shown in Table 2.

Comparative example  4 to 7

The same procedure as in Example 1 was carried out except that the size of the silica particles was changed to the size shown in Table 2.

Comparative example  8 ~ 9

It carried out similarly to Example 1 except having changed the draft ratio in the ratio of Table 2.

The composition and process conditions of the raw materials used in the examples and comparative examples, and the main physical properties of the masterbatch, undrawn yarn and drawn yarn thus obtained are shown in Tables 1 and 2, respectively.

Referring to Tables 1 and 2, Examples 1 to 3 and Comparative Examples 1 to 3 according to the content of the silica particles, Comparative Examples 1 to 2 is not added to the silica or its content is too low crystallization by the silica particles There was no retardation effect, and in comparison, 3 has a high silica content, and thus the semi-crystallization rate is increased, and thus the crystallinity of undrawn yarn is high.

In Comparative Examples 4 to 7 using silica particles having a size of silica particles having a size of 3, 32, 35, and 40 nm outside the average particle size range (5-30 nm) defined herein, Comparative Example 1, which did not include silica particles, was used. It can be seen that the semicrystallization time is similar or reduced compared to In other words, it is generally known that the smaller the silica particles, the larger the crystallization retardation effect is. However, as a result of adding the silica particles having the actual particle size of 3 nm, the semi-crystallization time is reduced compared to the case where the silica particles are not added. The crystallinity of was higher than 50%. In addition, when the size of the silica particles exceeds 30 nm, the crystallization delay effect does not appear, it can be seen that the crystallization proceeds rapidly due to the nucleation of the silica particles to increase the crystallinity of the undrawn yarn.

On the other hand, Comparative Example 8 in which the draft falls short of the range (300 to 400 times) determined by the present application has low crystallinity, and thus high strength is not expressed. This became impossible and high strength was not expressed.

Claims (5)

(S1) preparing a polyethylene-nano silica particle masterbatch by mixing polyethylene pellets having a crystallinity of 60 to 65% and nano silica particles having an average particle diameter of 5 to 30 nm at 0.01 to 0.3 parts by weight based on 100 parts by weight of polyethylene;
(S2) The polyethylene-nano silica particle masterbatch is put into an extruder having a temperature of 260 to 280 ° C. to melt polyethylene, and then passed through a spinneret having a temperature of 280 to 300 ° C. to contain polyethylene nanoparticles. Preparing a multifilament;
(S3) simultaneously cooling the polyethylene multifilament containing the nano-silica particles by 300 to 400 times while preparing a non-drawn yarn having a crystallinity of 40 to 50%; And
(S4) high-strength polyethylene including nano-silica particles comprising the step of stretching the unstretched yarn 18 times or more while passing through a heating chamber having a temperature of 100 to 120 ℃ to produce a polyethylene multifilament stretched yarn having a crystallinity of 80% or more Method for manufacturing multifilament drawn yarns. The method of claim 1,
The method of producing a high-strength polyethylene multifilament drawn yarn containing nano-silica particles, characterized in that to further prepare a polyethylene-nano silica particles masterbatch by adding a compatibilizer in the step (S1). The method of claim 2,
The compatibilizer is a styrene-ethylene-butylene-styrene (SEBS) copolymer, maleic anhydride-grafted polypropylene (MAN-g-PP) and mixtures thereof Method for producing a high strength polyethylene multifilament drawn yarn containing nano-silica particles, characterized in that any one selected from the group consisting of. 4. The method according to any one of claims 1 to 3,
The nano silica particles are a method of producing a high strength polyethylene multifilament drawn yarn containing nano silica particles, characterized in that the surface is modified with a surfactant. 5. The method of claim 4,
The surfactant is a method of producing a high strength polyethylene multifilament drawn yarn containing nano silica particles, characterized in that the cationic surfactant of the quaternary ammonium salt.