Method for producing porous fiber

Abstract

A method for manufacturing a porous fiber, comprising the steps of: performing an esterification and copolymerization step to react terephthalic acid, ethylene glycol, 5-sulfoisophthalic acid sodium salt, and a multi-branched chain monomer comprising trimethylolpropane or neopentyl glycol to form a soluble polyester; carrying out a fibration step, and carrying out co-spinning on the conventional polyester and the soluble polyester to form polyester fibers; and performing a refining step including dissolving the soluble polyester in the polyester fiber to form a plurality of holes in the polyester fiber. The porous fiber manufactured by the manufacturing method of the porous fiber disclosed by the invention has the functions of light weight, air permeability and moisture removal.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a fiber, and more particularly to a method for manufacturing a porous fiber. Background Art

[0002] In recent years, as people's requirements for quality of life have gradually increased, the comfort of wearing clothing has begun to become an important consideration when purchasing clothing. Functional clothing that adjusts to the temperature difference between autumn and winter, air-conditioned environment, and temperature conditions and body temperature changes during exercise has become an emerging product in today's textile market. Porous fibers have functions such as light weight, breathability, and moisture removal, but it is difficult to control the formation of holes during the manufacturing process (for example, the number, size, distribution density, etc. of holes), and the process is cumbersome and does not meet cost requirements. Therefore, how to provide a method for manufacturing porous fibers with convenience is a topic that people in this field are actively studying. Summary of the invention

[0003] The present disclosure provides a method for manufacturing porous fibers, wherein the porous fibers manufactured by the method have the functions of being light, breathable, and moisture-wicking.

[0004] According to some embodiments of the present disclosure, a method for manufacturing porous fibers includes: performing an esterification and copolymerization step to react terephthalic acid, ethylene glycol, sodium 5-sulfonate of isophthalic acid, and a multi-branched monomer to form a soluble polyester, wherein the multi-branched monomer includes trimethylolpropane or neopentyl glycol; performing a fiberization step to co-spin conventional polyester and the soluble polyester to form polyester fibers; and performing a refining step, including dissolving the soluble polyester in the polyester fibers to form a plurality of pores in the polyester fibers.

[0005] In some embodiments of the present disclosure, when terephthalic acid and 5-sodium sulfoisophthalic acid are 100 mol %, the 5-sodium sulfoisophthalic acid is 5 mol % to 15 mol %.

[0006] In some embodiments of the present disclosure, when the ethylene glycol and the multi-branched monomer are 100 mol %, the multi-branched monomer is 0.5 mol % to 5.0 mol %.

[0007] In some embodiments of the present disclosure, the conventional polyester is polyethylene terephthalate.

[0008] In some embodiments of the present disclosure, when the polyester fiber accounts for 100 wt %, the soluble polyester accounts for 6 wt % to 10 wt %.

[0009] In some embodiments of the present disclosure, in the refining step, the removal rate of the soluble polyester is 1.96% to 7.10%.

[0010] In some embodiments of the present disclosure, when an alkaline refining agent is used for the refining step, the concentration of the alkaline refining agent is 1 g NaOH / L to 3 g NaOH / L, and the bath ratio of the refining step is 1:10 to 1:20.

[0011] In some embodiments of the present disclosure, when the soluble polyester is subjected to a hot water dissolution test alone, the dissolution rate of the soluble polyester is 97.2% to 99.9%.

[0012] In some embodiments of the present disclosure, when a hot water dissolution test is performed using an alkaline refining agent, the concentration of the alkaline refining agent is less than or equal to 1 g NaOH / L, and the bath ratio of the hot water dissolution test is 1:20 to 1:100.

[0013] In some embodiments of the present disclosure, no alkaline refining agent is added in the hot water dissolution test.

[0014] According to the above-mentioned embodiments of the present disclosure, the present disclosure improves the dissolution rate of the soluble polyester by introducing multi-branched monomers, thereby directly completing the dissolution in the fiber refining step to form porous fibers without the need for an additional high-alkali concentration dissolution step, and can omit the conventional tedious step of filling the fibers with inorganic substances to create pores, thereby greatly improving the process convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to make the above and other objects, features, advantages and embodiments of the present disclosure more clearly understood, the accompanying drawings are described as follows:

[0016] Figure 1 A schematic diagram illustrating a process of manufacturing a porous fiber according to some embodiments of the present disclosure; and

[0017] Figure 2 Scanning electron microscope (SEM) images of porous fibers according to some embodiments of the present disclosure are shown.

[0018]

Explanation of symbols

[0019] S10~S30: Step 100: Porous Fiber

[0020] H: Hole DETAILED DESCRIPTION

[0021] The following will disclose multiple embodiments of the present disclosure with the accompanying drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary and therefore should not be used to limit the present disclosure. In addition, in order to simplify the drawings, some conventional structures and components will be illustrated in a simple schematic manner in the drawings. In addition, for the convenience of readers, the sizes of the components in the drawings are not drawn according to the actual scale.

[0022] The present disclosure provides a method for manufacturing porous fibers, which includes co-spinning conventional polyester and soluble polyester. By introducing multi-branched monomers during the preparation of the soluble polyester, the dissolution rate of the soluble polyester can be increased, so that the dissolution is directly completed in the fiber refining step to form a porous fiber with multiple holes, without the need for an additional high-alkali concentration dissolution step. On the other hand, the introduction of multi-branched monomers will not cause a large difference in viscosity between the soluble polyester and conventional polyester, which can ensure that the soluble polyester and conventional polyester have high dispersibility, thereby facilitating co-spinning. In addition, the present disclosure directly generates holes in the porous fiber by dissolving organic matter, thereby omitting the cumbersome steps of conventionally making holes by filling with inorganic substances.

[0023] Figure 1 A schematic flow chart of a method for manufacturing porous fibers according to some embodiments of the present disclosure is shown. The method for manufacturing porous fibers includes steps S10 to S30, and steps S10 to S30 can be performed in sequence, for example. In step S10, esterification and copolymerization steps are performed to form soluble polyester. In step S20, a fiberization step is performed to co-spin conventional polyester and soluble polyester to form polyester fibers. In step S30, a refining step is performed to form a plurality of pores in the polyester fibers. In the following description, steps S10 to S30 will be described in more detail.

[0024] In step S10, an esterification and copolymerization step is performed to form a soluble polyester. Specifically, in this step, terephthalic acid, ethylene glycol, sodium 5-sulfoisophthalic acid and a multi-branched monomer are subjected to an esterification and copolymerization reaction to form a soluble polyester, wherein the multi-branched monomer includes trimethylolpropane or neopentyl glycol. Compared to conventional polyesters such as polyethylene terephthalate, since the monomers used to prepare the soluble polyester include sodium 5-sulfoisophthalic acid, which is a polar monomer, the soluble polyester can be made water-soluble, which is beneficial for the soluble polyester to undergo a refining (dissolving) step based on an aqueous solution. In other words, the water solubility of the soluble polyester can be adjusted by adjusting the content of sodium 5-sulfoisophthalic acid. On the other hand, since the monomers used to prepare the soluble polyester include multi-branched monomers, the viscosity of the soluble polyester can be increased, making the viscosity of the soluble polyester close to the viscosity of conventional polyester, which is beneficial to improving the compatibility of the soluble polyester and conventional polyester during the fiberization step (spinning step).

[0025] In some embodiments, the esterification and copolymerization steps may include an esterification reaction and a copolymerization reaction performed sequentially. In some embodiments, the esterification reaction may be promoted by a catalyst such as titanium butoxide, the reaction temperature may be 255° C. to 265° C., and the reaction pressure may be 1.5 kg / cm 2 Up to 2.5kg / cm 2 , and the reaction time may be 2.5 hours to 3.5 hours. In some embodiments, the copolymerization reaction may be promoted by a catalyst such as antimony acetate (Sb(Ch3COO)2), the reaction temperature may be 265°C to 275°C, the reaction pressure may be 1.0 torr to 2.5 torr, and the reaction time may be 3 hours to 4 hours. By combining the above-mentioned process conditions of esterification reaction and copolymerization reaction, the efficiency of esterification and copolymerization can be improved, thereby improving the yield of soluble polyester.

[0026] In some embodiments, when the acid monomer is 100 mol%, that is, when terephthalic acid and 5-sodium sulfoisophthalic acid are 100 mol%, 5-sodium sulfoisophthalic acid may be greater than or equal to 5 mol% and less than or equal to 15 mol%, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14 mol% or in the interval formed by any of the aforementioned values. In detail, if the proportion of sodium 5-sulfonate isophthalic acid is less than 5 mol%, it is easy to cause the water solubility of the soluble polyester to be low, thereby reducing the dissolution effect of the soluble polyester in the refining step, or it may take a longer time to dissolve; if the proportion of sodium 5-sulfonate isophthalic acid is greater than 15 mol%, it will cause the proportion of terephthalic acid to be relatively reduced, which may easily make the physical properties of the soluble polyester differ greatly from those of conventional polyester, resulting in low compatibility between the soluble polyester and conventional polyester, which is not conducive to co-spinning, or other monomers need to be added to make the physical properties of the soluble polyester closer to those of conventional polyester.

[0027] In some embodiments, when the alcohol monomer is 100 mol%, that is, when ethylene glycol and the multi-branched monomer are 100 mol%, the multi-branched monomer may be greater than or equal to 0.5 mol% and less than or equal to 5.0 mol%, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 mol% or in the interval formed by any of the aforementioned values. In detail, if the proportion of the multi-branched monomer is less than 0.5 mol%, it is easy to cause the viscosity of the soluble polyester to be unable to be improved and the viscosity difference with the conventional polyester is large, thereby causing the compatibility of the soluble polyester with the conventional polyester to be low, which is not conducive to co-spinning; if the proportion of the multi-branched monomer is greater than 5.0 mol%, it is easy to cause the other physical properties of the soluble polyester and the conventional polyester to be different, which is also not conducive to improving the compatibility of the soluble polyester with the conventional polyester. Overall, by adjusting the proportion of the multi-branched monomer, the overall properties of the soluble polyester and the conventional polyester can be made more similar, which is beneficial to the subsequent fiberization step.

[0028] In step S20, a fiberization step is performed to spin conventional polyester and soluble polyester together to form polyester fibers. In some embodiments, the conventional polyester may be, for example, polyethylene terephthalate. Since the monomers used to prepare the soluble polyester disclosed herein include terephthalic acid and ethylene glycol, when the conventional polyester is polyethylene terephthalate, the compatibility of the soluble polyester with the conventional polyester can be improved. In some embodiments, when the polyester fiber is 100wt%, the soluble polyester may be greater than or equal to 6wt% and less than or equal to 10wt% (e.g., 7, 8, 9wt% or in the interval formed by any of the aforementioned values), so as to form sufficient pores in the porous fiber during the subsequent refining step and maintain the structural integrity of the porous fiber. Specifically, if the proportion of the soluble polyester is less than 6wt%, the number of holes in the porous fiber may be low or the hole size may be small, which is not conducive to the porous fiber to achieve the effects of air permeability, moisture removal and light weight; if the proportion of the soluble polyester is greater than 10wt%, the number of holes may be large or the hole size may be large, thereby destroying the structural integrity of the porous fiber and causing insufficient fiber strength. After this step, a polyester fiber containing conventional polyester and soluble polyester can be obtained.

[0029] In step S30, a refining step is performed to remove impurities such as oil, slurry, rust or dust attached to the surface of the polyester fiber during spinning. Specifically, an alkaline refining agent containing sodium hydroxide (NaOH) can be used for the refining step to facilitate the removal of impurities. In some embodiments, the concentration of the alkaline refining agent may be greater than or equal to 1g NaOH / L and less than or equal to 3g NaOH / L, and the bath ratio of the refining step (volume of alkaline refining agent: volume of water) may be greater than or equal to 1:10 and less than or equal to 1:20. When the concentration and bath ratio of the alkaline refining agent fall within the above range, it is beneficial to completely remove impurities on the surface of the polyester fiber and simplify the process. In detail, if the concentration of the alkaline refining agent is less than 1g NaOH / L or the bath ratio is greater than 1:20, impurities attached to the surface of the polyester fiber are likely to remain; if the concentration of the alkaline refining agent is greater than 3g NaOH / L or the bath ratio is less than 1:10, it will not be of obvious help in further removing impurities, and will also increase the complexity of waste liquid treatment.

[0030] It is worth noting that, since the soluble polyester disclosed in the present invention has a high dissolution rate, the polyester fiber containing the soluble polyester can be directly dissolved in the aforementioned low alkali concentration refining step to form a porous fiber with multiple holes, without the need for an additional high alkali concentration dissolution step, and the tedious step of conventionally making holes by filling with inorganic substances can be omitted, thereby greatly improving the convenience of the process. In other words, the refining step disclosed in the present invention further includes dissolving the soluble polyester in the polyester fiber to form multiple holes in the polyester fiber. In some embodiments, the time of the refining step may be greater than or equal to 25 minutes and less than or equal to 35 minutes. In the present disclosure, it is shown that the refining and dissolution of the fiber can be completed simultaneously under the premise of meeting the time of the industry's refining process, thereby greatly improving the process efficiency. Please refer to Figure 2 , which depicts a scanning electron microscope (SEM) image of a porous fiber 100 according to some embodiments of the present disclosure. From the SEM image, it can be observed that the density of the holes H in the porous fiber 100 is high and the distribution is uniform.

[0031] In some embodiments, during the refining step, the dissolution rate of the soluble polyester in the polyester fiber can be greater than or equal to 1.96% and less than or equal to 7.10% (e.g., 2, 3, 4, 5, 6, 7%), thereby forming sufficient holes in the polyester fiber to achieve the effects of air permeability, moisture removal and lightness, and maintaining the structural integrity of the porous fiber, so that the porous fiber has high fiber strength. In some embodiments, when the soluble polyester is subjected to a hot water dissolution test alone (the test temperature is 100° C.), the dissolution rate of the soluble polyester can be greater than or equal to 97.2% and less than or equal to 99.9%, indicating that the soluble polyester can exhibit an excellent dissolution effect. The above-mentioned hot water dissolution test can be performed on the soluble polyester using the alkaline refining agent described above, wherein the concentration of the alkaline refining agent can be less than or equal to 1g NaOH / L, and the bath ratio of the hot water dissolution test can be greater than or equal to 1:20 and less than or equal to 1:100; or no alkaline refining agent can be added, that is, the hot water dissolution test can be performed in a neutral (pH value 6-8) environment. In general, regardless of whether an alkaline refining agent is used, the dissolution rate of the soluble polyester can be greater than or equal to 97.2% and less than or equal to 99.9%.

[0032] In the following description, various evaluations will be conducted on the porous fibers disclosed in the present disclosure to specifically describe the efficacy of the present disclosure. It should be understood that the embodiments described below are only illustrative, and the materials used, their contents and proportions, processing details and processing procedures, etc. may be appropriately changed without exceeding the scope of the present disclosure. Therefore, the present disclosure should not be interpreted restrictively by the embodiments described below.

[0033] <Experimental Example 1: Dissolution Test of Dissolvable Polyester>

[0034] In this experimental example, the soluble polyester of each embodiment is subjected to a hot water dissolution test to measure the dissolution rate of the soluble polyester. In detail, in this experimental example, terephthalic acid, sodium 5-sulfoisophthalic acid, ethylene glycol and a multi-branched monomer are subjected to esterification and copolymerization to form the soluble polyester of each embodiment, and the soluble polyester is weighed (original weight W1) and dissolved, and then weighed after dissolution (weight after dissolution W2) to calculate the dissolution rate of the soluble polyester (formula: [(W1-W2) / W1]×100%). The detailed description of each embodiment is shown in Table 1, and the hot water dissolution test conditions and dissolution results are shown in Table 2.

[0035] Table 1

[0036]

[0037]

[0038] Table 2

[0039]

[0040] From the results in Table 2, it can be seen that when using an alkaline refining agent to perform hot water dissolution tests, the soluble polyesters of each embodiment have a dissolution rate close to 100%, and the required alkali concentration is low. For Example 2, when the bath ratio is further adjusted from 1:100 to 1:20, the soluble polyester can have a dissolution rate close to 100% without even adding an alkaline refining agent. It can be seen that the soluble polyester disclosed in the present invention can exhibit a very excellent dissolution effect.

[0041] <Experimental Example 2: Refining Test of Polyester Fiber>

[0042] In this experimental example, the soluble polyester of Example 4 was co-spun with polyethylene terephthalate to form the polyester fibers of each example (wherein the polyester fibers were extended false twist yarns with a specification of 75d / 72f), and the polyester fibers were weighed (original weight W3) and subjected to a refining step, and then weighed after the refining step (weight after refining W4) to calculate the dissolution rate of the soluble polyester in the polyester fibers (formula: [(W3-W4) / W3]×100%). The detailed description, refining test conditions and dissolution results of each example are shown in Table 3.

[0043] Table 3

[0044]

[0045] From the results in Table 3, it can be seen that after the polyester fibers of each embodiment are subjected to the refining step, the soluble polyester in the polyester fibers of each embodiment has a good dissolution rate. Thus, the formed porous fibers can have holes of a suitable number and size, thereby achieving the effects of air permeability, moisture removal and lightness, and maintaining a certain structural integrity.

[0046] According to the above-mentioned embodiments of the present disclosure, the present disclosure improves the dissolution rate of the soluble polyester by introducing multi-branched monomers, thereby directly completing the dissolution in the fiber refining step to form porous fibers without the need for an additional high-alkali concentration dissolution step, and can omit the conventional tedious step of filling the fibers with inorganic substances to create pores, thereby greatly improving the process convenience.

[0047] Although the present disclosure has been disclosed in the above embodiments, it is not intended to limit the present disclosure. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure should be determined by the attached claims.

Claims

1. A method for producing a porous fiber, characterized in that: include: An esterification and copolymerization step is performed to react terephthalic acid, ethylene glycol, sodium 5-sulfoisophthalate and a multi-branched monomer to form a soluble polyester, wherein the multi-branched monomer includes trimethylolpropane or neopentyl glycol; performing a fiberizing step to co-spin a conventional polyester and the soluble polyester to form a polyester fiber; and A refining step is performed, including dissolving the soluble polyester in the polyester fiber to form a plurality of pores in the polyester fiber.

2. The method for producing a porous fiber according to claim 1, wherein: When the terephthalic acid and the 5-sodium sulfoisophthalic acid salt are 100 mol %, the 5-sodium sulfoisophthalic acid salt is 5 mol % to 15 mol %.

3. The method for producing a porous fiber according to claim 1, wherein: When the ethylene glycol and the multi-branched monomer are 100 mol %, the multi-branched monomer is 0.5 mol % to 5.0 mol %.

4. The method for producing a porous fiber according to claim 1, wherein: The conventional polyester is polyethylene terephthalate.

5. The method for producing a porous fiber according to claim 1, wherein: When the polyester fiber accounts for 100 wt %, the soluble polyester accounts for 6 wt % to 10 wt %.

6. The method for producing a porous fiber according to claim 5, wherein: In the refining step, the removal rate of the soluble polyester is 1.96% to 7.10%.

7. The method for producing a porous fiber according to claim 1, wherein: When an alkaline refining agent is used for the refining step, the concentration of the alkaline refining agent is 1 g NaOH / L to 3 g NaOH / L, and the bath ratio of the refining step is 1:10 to 1:

20.

8. The method for producing a porous fiber according to claim 1, wherein: When the soluble polyester is subjected to a hot water dissolution test alone, the dissolution rate of the soluble polyester is 97.2% to 99.9%.

9. The method for producing a porous fiber according to claim 8, wherein: When an alkaline refining agent is used to perform the hot water dissolution test, the concentration of the alkaline refining agent is less than or equal to 1 g NaOH / L, and the bath ratio of the hot water dissolution test is 1:20 to 1:

100.

10. The method for producing a porous fiber according to claim 8, wherein: In the hot water dissolution test, no alkaline refining agent was added.

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