PREPARATION METHOD OF FIBER

Abstract

A preparation method of a fiber is provided. In the preparation method of the fiber, a polymer is dissolved in a mixing solution of an ionic liquid and a salt to form a spinning viscose, wherein the salt includes KCl, KBr, KOAc, NaBr, ZnCl.sub.2 or a combination thereof. Afterwards, the spinning viscose is used as a material to perform a spinning process so as to form a fiber.

Claims

1. A preparation method of a fiber, comprising: dissolving a polymer in a mixing solution including an ionic liquid and a salt to form a spinning viscose, wherein the polymer comprises cellulose or poly-metaphenylene isophthalamide, the salt includes KCl, KBr, KOAc, NaBr, ZnCl.sub.2 or a combination thereof, and a weight ratio of the salt and the ionic liquid is 10:90 to 0.1:99.9; and performing a spinning process using the spinning viscose as a material to form a fiber.

2. The method of claim 1, wherein the ionic liquid is composed of a cation and an anion, and the cation is alkyl imidazole type and the cation includes a structure of Formula 1: ##STR00003## wherein R.sub.1 and R.sub.2 are respectively a alkyl group having 1 to 4 carbon atoms; the anion is Cl.sup., Br or CH.sub.3COO.sup..

3. The method of claim 1, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium acetate.

4. The method of claim 1, wherein the polymer is 5 wt % to 20 wt % by weight based on a total weight of the spinning viscose.

5. The method of claim 1, wherein the polymer is dissolved in the mixing solution at a temperature of 60 C. to 80 C.

6. The method of claim 1, wherein the spinning process is a wet spinning method or a dry-jet wet spinning method.

Description

DESCRIPTION OF THE EMBODIMENTS

[0017] According to an embodiment of the invention, a preparation method of a fiber is provided. First, a polymer is dissolved in a mixing solution including an ionic liquid and a salt to form a spinning viscose. In the present embodiment, the polymer is cellulose or poly-metaphenylene isophthalamide, for example. The salt is KCl, KBr, KOAc, NaBr, ZnCl.sub.2 or a combination thereof, for example. The ionic liquid is composed of a cation and an anion, and the cation is alkyl imidazole type including a structure illustrated in Formula 1:

##STR00002##

[0018] wherein R.sub.1 and R.sub.2 are respectively a alkyl group having 1 to 4 carbon atoms, and the anion is Cl.sup., Br.sup. or CH.sub.3COO.sup., for example. In another embodiment, the ionic liquid is 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), for example.

[0019] In the present embodiment, the salt is added into the ionic liquid. A weight ratio of the salt and the ionic liquid is 10:90 to 0.1:99.9, preferably 3:97 to 1:99, and more preferably 3:97, for example. After adding the salt into the ionic liquid, a polarity of the ionic liquid is increased, so as to increase polymer solubility.

[0020] In the present embodiment, the polymer is 5 wt % to 20 wt % by weight based on a total weight of the spinning viscose, for example. In another embodiment, the polymer is 10 wt % to 15 wt % by weight based on the total weight of the spinning viscose, for example. In yet another embodiment, the polymer is 10 wt % by weight based on the total weight of the spinning viscose, for example.

[0021] It is worth mentioning that, the polymer is dissolved in the mixing solution of the ionic liquid and the salt at a temperature of 60 C. to 80 C. The process temperature of using NMMO in the prior art is 110 C. to 130 C., which consumes more energy. In comparison, using the ionic liquid of the invention lowers the overall process temperature effectively, so polymer degradation is improved with energy conservation effects. Besides, the ionic liquid also has advantages including no volatility and high chemical stability.

[0022] Afterwards, a spinning process is performed by using the aforementioned spinning viscose as a material to form a fiber. In the present embodiment, the spinning process spins the spinning viscose through a dry-jet wet spinning method, for example, and the spinning dope enters into coagulation bath (such as ethanol, water or a combination thereof) and then washed in water, then the fiber preparation is completed. In other embodiments, a wet spinning method can also be used to perform the spinning process.

[0023] Experimental examples will be used to explain the fiber preparation of the aforementioned embodiments and characteristics thereof in detail. However, the following Experimental examples are not intended to limit the invention.

Experimental Example

[0024] To prove the excellent fiber strength of the fiber prepared by the fiber preparation method of the invention, and the overall process temperature is lower with energy conservation effects, the following Experimental Examples are performed.

Fiber Preparation

Example 1

[0025] 48.5 g ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) and 1.5 g (3 wt %) KOAc are mixed and dissolved at 60 C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60 C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 2

[0026] 48.5 g ionic liquid [EMIM]OAc and 1 g (2 wt %) KOAc and 0.5 g (1 wt %) KBr are mixed and dissolved at 60 C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60 C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 3

[0027] 48.5 g ionic liquid [EMIM]OAc and 1.5 g (3 wt %) KBr are mixed and dissolved at 60 C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60 C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 4

[0028] 48.25 g ionic liquid [EMIM]OAc and 1.75 g (3.5 wt %) KBr are mixed and dissolved at 60 C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 60 C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 5

[0029] 48.5 g ionic liquid [EMIM]OAc and 1.5 g (3 wt %) KCl are mixed and dissolved at 80 C. to form a mixing solution. Afterwards, 5 g cellulose is added, and mixed and dissolved at 80 C. to form a spinning viscose. The spinning viscose is used as a material to perform a spinning process, and a cellulose fiber is formed through a dry-jet wet spinning method.

Example 6

[0030] 48.5 g ionic liquid [EMIM]OAc and 1.5 g (3 wt %) KBr are mixed and dissolved at 80 C. to form a mixing solution. Afterwards, 10 g poly-metaphenylene isophthalamide is added, and mixed and dissolved at 80 C. to form a spinning viscose.

Comparative Example

[0031] 5 g cellulose is added into 50 g ionic liquid [EMIM]OAc, and mixed and dissolved at 60 C. Afterwards, a spinning process is performed, and a fiber is formed through a dry-jet wet spinning method.

Measurement of Fiber Strength

[0032] Afterwards, as for the cellulose fibers of Example 1 to Example 5 and the cellulose fiber of Comparative Example, the measurement of fiber strength are performed by ASTM D3822 measurement method, and the measurement results are shown in the following Table 1.

TABLE-US-00001 TABLE 1 Salt and Fiber strength Ionic liquid concentration (gf/den) Example 1 [EMIM]OAc 3 wt % KOAc 4.6 Example 2 [EMIM]OAc 2 wt % KOAc/ 3.8 1 wt % KBr Example 3 [EMIM]OAc 3 wt % KBr 4.1 Example 4 [EMIM]OAc 3.5 wt % KBr 4.9 Example 5 [EMIM]OAc 3 wt % KCl 3.5 Comparative [EMIM]OAc 0 3.2 Example

[0033] As shown in Table 1, Comparative Example uses only ionic liquid to dissolve the cellulose, and the fiber strength of the cellulose fiber is 3.2 gf/den. In comparison, Example 1 to Example 5 perform cellulose fiber preparations according to the preparation method of fiber provided by the invention, wherein the ionic liquid is [EMIM]OAc, and the salts including 3 wt % KOAc, 2 wt % KOAc/1 wt % KBr, 3 wt % KBr, 3.5 wt % KBr or 3 wt % KCl is added into the ionic liquid respectively. Afterwards, the cellulose is dissolved in a mixing solution of the ionic liquid and the salt, and the fiber is formed through a dry-jet wet spinning method. As shown in Table 1, the fiber strengths of the cellulose fibers formed in Example 1 to Example 5 are 4.6 gf/den, 3.8 gf/den, 4.1 gf/den, 4.9 gf/den and 3.5 gf/den, respectively. Therefore, compared to the cellulose fiber prepared by Comparative Example, the fiber strengths of the fibers prepared in Example 1 to Example 5 are obviously higher. In other words, fiber strength is obviously improved through the preparation method of fiber provided by the invention.

[0034] To sum up, the preparation method of fibers provided by the invention increases fiber solubility and strength. The ionic liquid has high chemical stability and high heat stability, but with no volatility, and the ionic liquid can be recycled and reused. After adding the salt into the ionic liquid, the polarity is enhanced, the polymer solubility is improved, and the fiber strength is effectively increased. Besides, the process temperature is also lowered to improve the energy consumption of the process. In addition, compared to the prior art using NMMO, the preparation method of fiber provided by the invention does not require additional stabilizing agent or DMSO, so the recycling cost is reduced with industrial values. The invention also provides a spinning viscose with good spinnability, and fibers with higher strength can be obtained through wet spinning method or dry-jet wet spinning method.

[0035] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.