KR100627171B1 - Method for preparing high-tenacity polyvinyl alchol fiber and product manufactured thereby - Google Patents

Abstract

The present invention relates to a method of producing high-strength PVA fiber by stretching the polyvinyl alchol (PVA) spinning stock solution only by hot stretching once without stretching.

Method for producing high-strength PVA fiber according to the present invention is characterized in that 2 to 35% by weight of the polyvinyl alcohol spinning stock solution obtained by the non-expanded yarn by wet or wet spinning method, and then hot drawn to one end using a hot stove of 3m or less. It is done.

According to the present invention, high-strength PVA fibers can be economically produced by hot stretching at a total draw ratio of 15 or more using a hot stove of a minimum length.

Polyvinyl alcohol, high strength, high magnification, hot drawing, hot stove

Description

Method for preparing high-strength polyvinyl alcohol fiber and thereby high strength polyvinyl alcohol fiber {Method for preparing high-tenacity polyvinyl alchol fiber and product manufactured}

The present invention relates to a method for producing high strength polyvinyl alcohol fibers, and more particularly, after obtaining a non-stretched yarn without wet stretching a polyvinyl alcohol spinning stock solution, high-strength polyvinyl chloride stretching by high magnification only once stretching without multi-step stretching. It relates to a method for producing alcohol fibers and to high strength polyvinyl alcohol fibers thereby.

Polyvinyl alchol (PVA) has excellent properties such as excellent linearity, flat Zig-Zag structure, high crystallinity, excellent alkali resistance and good adhesion withstand strong pH above pH13.5. Due to these characteristics, high strength, high modulus PVA fibers are possible, and thus, they are widely received as industrial fibers such as reinforcement materials such as cement, concrete, plastic and rubber, asbestos substitute materials, and tire cords.

Until now, various methods such as a dry method, a wet method, and a wet method are used for spinning a high-strength PVA fiber, but recently, a wet and dry spinning method capable of high magnification is mainly used. Japanese Laid-Open Patent Publication No. 5-18514 discloses a method for producing a high strength PVA fiber by stretching in multiple stages with a total draw ratio of 15 times or more in a hot stove having a length of about 6 to 10 m. However, in this case, the length of the hot stove is too long to occupy a lot of space, and there is a problem in that the economic efficiency is lowered by the multi-stage stretching. As another method, Japanese Patent Laid-Open No. 10-310939 introduces a method for producing high strength PVA fibers by simultaneously performing wet stretching and thermal stretching, with a total draw ratio of 15 times or more. However, in the case of high wet drawing, the crystallization of the fiber proceeds in advance, and thus, a draw ratio may not be obtained in the case of hot drawing. In addition, the multi-stretching at the time of hot stretching is economical and the proper temperature gradient is absolutely required, as the high temperature of the hot stove is continuously imposed on the yarn, causing fluff phenomenon or single thread break.

While addressing these process shortcomings, there is an urgent need to develop a method for producing high strength PVA fibers with higher tensile strength.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, it is possible to economically produce high-strength PVA fibers by stretching the PVA spinning stock solution without performing any wet stretching at all, and stretching once without multistage stretching. The purpose is to provide a method.

Another object of the present invention is to provide a high strength PVA fiber having a total draw ratio of 15 or more and a tensile strength of 15 g / d or more by using the above method.

Method for producing a high-strength PVA fiber according to the present invention for achieving the above object is a step of dissolving 2 to 35% by weight of polyvinyl alcohol in an organic solvent to make a polyvinyl alcohol spinning stock solution, the spinning stock solution is a wet or wet spinning method Obtaining the undrawn yarn and characterized in that it comprises the step of hot stretching the undrawn yarn to one end using a hot stove.

The polyvinyl alcohol has a degree of polymerization of 1,500 to 7,000 and a degree of reduction of 90 mol% or more, more preferably 99 mol% or more.

It is preferable that the length of a hot stove at the time of hot drawing is 3 m or less, the temperature of a hot stove is 180-230 degreeC, and the temperature of a feed roller is 70-100 degreeC.

In addition, by using the hot blast furnace is characterized in that the total draw ratio at the time of hot stretching to 15 or more to provide a high strength polyvinyl alcohol fiber with a tensile strength of 15g / d or more.

Hereinafter, the present invention will be described in more detail.

The present invention is economically economical without the occurrence of fluff phenomenon or single trimming that occurs during multistage stretching by performing only hot stretching using a short hot stove of 3m or less without performing wet stretching at all in the process of obtaining unstretched yarn with PVA spinning stock solution. It is characterized by making high strength PVA fibers.

PVA used in the present invention should be 90 mol% or more, more preferably 99 mol% or more. When the degree of PVA is lower than 90 mol%, there are many defects in the polymer, resulting in poor heat resistance.                     

Moreover, it is preferable to use the thing of the polymerization degree of PVA 1,500 or more and 7,000 or less, and, when considering economy, it is more preferable to use the thing of the polymerization degree 1,500-3,000. In general, as the degree of polymerization decreases, the strength of the fiber is lowered, so that when a degree of polymerization of less than 1,500 is used, it is difficult to form a high strength fiber.

In the present invention, the PVA is dissolved in an organic solvent to form a PVA spinning solution. The solvent used may be dimethyl sulfoxide (DMSO), water, ethylene glycol (EG) and the like, but dimethyl sulfoxide is most preferred in terms of solubility. The concentration of PVA in the spinning stock solution may be selected according to the spinning temperature and the stretching ratio of the fibers, and in the present invention, it is preferably 2 to 35% by weight.

The prepared spinning stock solution is spun by wet or wet spinning to obtain undrawn yarn. In this case, although methanol or ethanol may be mainly used as the coagulation bath, it is preferable to use methanol in terms of coagulation rate or solvent extraction rate.

The obtained non-drawn yarn is thermally stretched. The hot drawing process is very important for producing the high strength PVA fibers desired by the present invention. In the stretching process, there are non-contact hot air heating and contact roller heating, but in the roller heating method, filament is in contact with the roller surface, and excessive heat is transferred to the fiber, which causes undesirable fluff phenomenon. Therefore, it is more effective to use hot air heating in the production of high strength PVA fibers according to the present invention. At this time, the temperature of hot air can be extended | stretched with the high magnification to the range of 150-250 degreeC, More preferably, it is 180-230 degreeC. If the temperature of hot air is lower than 150 ℃, sufficient heat to penetrate the molecular chain does not penetrate into the fiber crystal region, so high magnification thermal stretching is impossible.If it exceeds 250 ℃, the fiber is decomposed due to the decomposition temperature of the fiber. This results in a drop in physical properties. The gas used in the hot stove can be either air or inert gas, but in terms of cost, air can be preferably used, and the hot wind flows in a direction opposite to the direction in which the yarn flows. It is preferable that it is 250 degreeC.

The temperature of the feed roller (feed roller), which is a roller just before entering the hot stove, is preferably 70 to 100 ° C., and when the temperature exceeds 100 ° C., excessive heat is transferred to the fiber in advance, so that the crystallization proceeds excessively on the roller surface. High magnification stretching is not possible, which is undesirable.

It is preferable that the hot stove used at the time of hot stretching according to the present invention has a length of 3 m or less. If the length of the hot stove is more than 3m, excessive heat is continuously applied to the yarn, which may cause fluffing, hyphae, and even single yarns.

By using the short hot blast furnace of 3m or less, once stretched, high-strength PVA fibers having a total draw ratio of 15 or more can be produced.

Hereinafter, embodiments of the present invention will be described, but the following examples are to be understood as merely illustrative of the present invention and not to limit the scope of the present invention.

Example 1                     

PVA having a molarity of 99 mol% and a polymerization degree of 1,700 was dissolved in dimethyl sulfoxide at a concentration of 22% by weight to prepare a PVA spinning stock solution. Unstretched yarn was prepared by performing a wet-and-dry spinning of the prepared spinning stock solution using a platinum nozzle having a diameter of 0.1 mm and 120 holes in a methanol coagulation bath at 70 ° C. The obtained undrawn yarn was wound up after drying, and then hot drawn using a 2.5m hot stove. At this time, the hot air inlet temperature was 205 ° C., the roller temperature was 70 ° C. to draw at a total draw ratio of 22.5 to prepare high-strength PVA fibers.

The tensile strength of the obtained PVA fibers was 21.5 g / d, the modulus of elasticity was 480 g / d, and no single yarn or fluff occurred during the stretching process for more than 72 hours.

Example 2

In the hot drawing process, the same method as in Example 1 was carried out except that the drawing process was performed with the length of the hot stove 3 m, the temperature of the hot stove 210 ° C, the temperature of the roller 80 ° C and the total draw ratio 20. High strength PVA fibers were made.

The tensile strength of the obtained PVA fiber was 19.5 g / d, and the elasticity modulus was 395 g / d.

Comparative Example 1

The spinning solution obtained in the same manner as in Example 1 was stretched at a draw ratio of 4 to obtain an undrawn yarn. The obtained non-drawn yarn was hot drawn under the same conditions as in Example 1, but it was impossible to make the total draw ratio 12 or more.

Comparative Example 2

A PVA fiber was manufactured in the same manner as in Example 1 except that the length of the hot stove was 6 m and the temperature of the roller was 120 ° C. in the hot drawing process.                     

PVA fiber according to the embodiment is a high-strength fiber with a tensile strength of 15g / d, elastic modulus of 300g / d or more it can be seen that it can be obtained by hot stretching once with a total draw ratio of 15 or more using a short hot stove of 3m or less.

Compared with the above example, in the case of hot stretching after the wet stretching as well as the hot stretching (Comparative Example 1), it was impossible to increase the total draw ratio to 12 times or more. In general, considering that the strength and elastic modulus increase proportionally with the draw ratio, it is evident that the obtained PVA fiber strength and elastic modulus are significantly reduced. In addition, fluff frequently occurred during hot stretching, and single trimming occurred every 20 minutes.

In addition, when the length of the used hot stove was lengthened (Comparative Example 2), excessive heat was transferred to the fibers passing through the rollers, causing the yarn to stick to the rollers, causing cracks and fluffs frequently. Single yarn occurred and smooth stretching was impossible.

According to the present invention, a high-strength PVA fiber having a total draw ratio of 15 or more and a tensile strength of 15 g / d or more can be manufactured by omitting a wet drawing process in the spinning process during the spinning process and using a hot stove having a minimum length.

In addition, the present invention can economically produce high-strength PVA fibers expressing the effect of multi-stretching by thermal stretching once, such high-strength PVA fibers for fishing nets or asbestos as well as industrial reinforcing materials such as cement, concrete, rubber It can also be used as a substitute.                     

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the present invention, and such modifications and variations are included in the appended claims. Belonging is natural.

Claims (6)

Dissolving 2 to 35% by weight of polyvinyl alcohol in an organic solvent to form a polyvinyl alcohol spinning stock solution; Obtaining undrawn yarn from the spinning stock solution by wet or wet spinning; And Thermally stretching the undrawn yarn to one end using a hot stove having a length of 3 m or less and a temperature of 180 to 230 ° C .; Method for producing a high strength polyvinyl alcohol fiber consisting of. The method of claim 1, The polyvinyl alcohol has a degree of polymerization of 1,500 to 7,000 and a method of producing a high strength polyvinyl alcohol fiber, characterized in that the degree of influence of 90 mol% or more. delete The method of claim 1, Method for producing the high strength polyvinyl alcohol fiber, characterized in that the temperature of the feed roller (feed roller) during the hot stretching is 70 to 100 ℃. The method of claim 1, The method of manufacturing the high strength polyvinyl alcohol fiber, characterized in that the total draw ratio at the time of hot stretching is 15 or more. A high strength polyvinyl alcohol fiber produced by the method of claim 1 having a tensile strength of 15 g / d or more.