Acetic acid-imitated polyester fiber and preparation process thereof

Abstract

The invention relates to the technical field of polyester fiber materials, and discloses an acetic acid-imitated polyester fiber and a preparation process thereof, and the preparation process comprises the following steps: preparing an epoxidized ether acylamino quaternary ammonium salt type end-capping reagent; an epoxy functional group of the epoxidized ether amido quaternary ammonium salt type end-capping reagent and a terminal hydroxyl functional group or a terminal carboxyl functional group on a molecular main chain in polyethylene terephthalate are subjected to a ring-opening reaction, so that end-capping modification treatment on polyethylene terephthalate is completed; the modified polyethylene terephthalate PET with flexible, moisture absorption and antistatic functions is prepared; modified polyethylene terephthalate PET is used as a raw material, the acetic acid-imitated polyester fiber is prepared through melt spinning and parallel drafting processes, and the fiber product not only has smooth touch feeling similar to that of cellulose acetate fiber and good moisture absorption and antistatic performance, but also retains good breaking strength, can be used in the field of textiles, and has wide application prospects. The wearing comfort of the polyester fiber textile is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber materials technology, specifically to an imitation acetate polyester fiber and its preparation process. Background Technology

[0002] Polyester fibers are generally polymeric materials obtained by the condensation polymerization of diacids and diols. Their structural units are linked by ester groups, and the ends of the molecular chains are usually hydroxyl or carboxyl groups. Among them, polyethylene terephthalate (PET) fiber (also known as polyester) is the main type of polyester fiber, accounting for more than 90% of polyester fibers.

[0003] Polyester fiber has advantages such as low cost, high strength, and good stability, and is widely used in the textile and apparel industry. However, polyester fiber has a rigid molecular chain, lacks polar hydrophilic groups, and has high crystallinity, with a moisture regain of only about 0.4% under standard conditions. Therefore, textiles made from polyester fiber usually have disadvantages such as a stiff hand feel, poor hydrophilicity and moisture absorption, and a tendency to generate static electricity, which greatly affects wearing comfort. Acetate fiber, on the other hand, has advantages such as a soft hand feel, good moisture absorption, and good drape. However, acetate fiber has high production costs, low breaking strength (usually 1.0-1.5 cN / dtex), and poor acid and alkali resistance, which limits its large-scale application.

[0004] Imitation acetate polyester fiber is made by modifying the molecular structure of polyester (such as PET) or by spinning it to give it a soft feel and good moisture absorption similar to acetate fiber. This improves the problems of poor antistatic properties and stuffiness and lack of breathability of traditional polyester fiber textiles, while retaining the advantages of low cost, high strength and good stability of polyester fiber, thus achieving complementary performance.

[0005] Research has found that the hydrophilic and hygroscopic modification of polyester fibers is mainly achieved by introducing hydrophilic groups (such as amide groups, hydroxyl groups, carboxyl groups, and other strongly polar groups) into the fiber molecular structure, or by changing the regularity of the molecular structure (such as introducing branches) and reducing the crystallinity of polyester, thereby improving the hydrophilic and hygroscopic properties of the fiber; in terms of hand feel modification, it is mainly achieved by introducing flexible segments into the fiber molecular structure.

[0006] In addition, there are existing reports on enhancing the antistatic properties of polyester fibers by introducing quaternary ammonium salt structures. This is because positively charged quaternary ammonium groups can attract negative charges accumulated on the fiber surface (such as static electricity generated by friction), and neutralize the charge through ionic conductivity, thereby playing an antistatic role. Summary of the Invention

[0007] To address the shortcomings of traditional polyester fibers, such as a stiff feel, poor hydrophilicity and moisture absorption, and susceptibility to static electricity, this invention develops a polyester acetate-like fiber. It possesses a soft touch similar to acetate fiber, as well as good moisture absorption and antistatic properties, while retaining the advantages of polyester fiber, such as low cost and high strength. It can be used in the textile field to significantly improve the wearing comfort of polyester fiber textiles.

[0008] A process for preparing imitation acetate polyester fiber includes the following steps:

[0009] Step 1: Preparation of epoxide ether-based amide-based quaternary ammonium salt end-capping agent;

[0010] Step 2: The epoxy functional groups of the epoxide ether-amide quaternary ammonium salt end-capping agent undergo a ring-opening reaction with the terminal hydroxyl or terminal carboxyl functional groups on the main chain of polyethylene terephthalate (PET) to complete the end-capping modification of PET and obtain a modified PET with flexible, hygroscopic and antistatic functions.

[0011] Step 3: Using the modified polyethylene terephthalate (PET) as raw material, imitation acetate polyester fiber is obtained through melt spinning and parallel drawing processes.

[0012] Preferably, the preparation method of the epoxide ether-amide quaternary ammonium salt type capping agent is as follows:

[0013] Using 4,7,10-trioxo-1,13-tridecanediamine as a raw material, an amidation reaction is carried out between the -NH2 functional group of 1 molar equivalent of 4,7,10-trioxo-1,13-tridecanediamine and the carboxyl functional group of 0.91-0.99 molar equivalent of ethylene glycol monomethyl ether propionic acid to generate an amide amino monomer.

[0014] A nucleophilic substitution reaction is carried out between the -NH2 functional group of 1 molar equivalent of an amide amino monomer and the bromine functional group of 1.91-1.99 molar equivalent of 6-bromohexane amide to generate an amide tertiary amine monomer.

[0015] By utilizing a nucleophilic substitution reaction mechanism, a quaternization reaction occurs between the tertiary amine functional group of a 1 molar equivalent amide-based tertiary amine monomer and the chlorine functional group of 1.1-1.2 molar equivalent epichlorohydrin, generating an epoxide ether-based amide-based quaternary ammonium salt end-capping agent.

[0016] Preferably, the amount of the epoxide ether-based amide-based quaternary ammonium salt end-capping agent in the modified polyethylene terephthalate (PET) is 5-15 wt% of the amount of PET.

[0017] Preferably, the process parameters for the melt spinning process are set as follows: the temperatures of the screw zones 1-4 are 220-230℃, 240-255℃, 240-260℃, and 250-260℃, respectively; the temperatures of the metering pump, the bend pipe, and the housing are all 255-260℃; and the spinning speed is 600-900m / min.

[0018] Preferably, the process parameters of the parallel drawing process are set as follows: the drawing speed is 100-300 m / min, the drawing ratio is 3-5 times, the hot plate temperature is controlled at 50-70℃ and the hot plate temperature is controlled at 120-140℃ during drawing.

[0019] An imitation acetate polyester fiber prepared according to the above process;

[0020] Preferably, the fineness of the imitation acetate polyester fiber is 120-180 dtex.

[0021] Preferably, the moisture regain of the imitation acetate polyester fiber is (1.6-2.3)%.

[0022] Preferably, the volume resistivity of the imitation acetate polyester fiber is (10) 8 -10 9 )Ω·cm.

[0023] Beneficial effects:

[0024] Based on molecular design principles, this invention first designed and synthesized an epoxide-based amide-based quaternary ammonium salt end-capping agent containing polyether flexible segments, hydrophilic amide groups (-CONH- and -CONH2), and antistatic quaternary ammonium salt groups. The agent used 4,7,10-trioxo-1,13-tridecanediamine as the bridging structure and ethylene glycol monomethyl ether propionic acid, 6-bromohexamide, and epichlorohydrin as raw materials.

[0025] Subsequently, through an epoxy-hydroxy / carboxyl ring-opening reaction, polyethylene terephthalate (PET) was modified by end-capping with an epoxy ether-amide quaternary ammonium salt type end-capping agent to obtain a modified PET containing polyether flexible segments, hydrophilic groups (amide groups introduced by the epoxy ether-amide quaternary ammonium salt type end-capping agent and hydroxyl groups generated by the ring-opening reaction), and antistatic quaternary ammonium salt groups, which has both flexible, hygroscopic and antistatic functions.

[0026] Finally, using the above-mentioned modified polyethylene terephthalate (PET) as raw material, a polyester-like acetate fiber was prepared by melt spinning and parallel stretching processes. This fiber possesses a soft touch similar to acetate fiber, good moisture absorption and antistatic properties, and retains good breaking strength.

[0027] Experimental results show that the imitation acetate polyester fiber prepared by this invention has significantly higher moisture regain, significantly lower bending stiffness and volume resistivity compared to conventional polyester fiber. It also achieves significant improvements in moisture absorption, softness and antistatic properties. Detailed Implementation

[0028] Example 1:

[0029] The preparation process of the epoxidized ether-amide quaternary ammonium salt type end-capping agent is as follows:

[0030] Step 1: Using 4,7,10-trioxo-1,13-tridecanediamine as a starting material, an amidation reaction is carried out between the -NH2 functional group of 1 molar equivalent of 4,7,10-trioxo-1,13-tridecanediamine and the carboxyl functional group of 0.95 molar equivalent of ethylene glycol monomethyl ether propionic acid to generate an amide-amino monomer with the following chemical structural formula:

[0031]

[0032] Step 2: A nucleophilic substitution reaction occurs between the -NH2 functional group of 1 molar equivalent of the amide-amino monomer and the bromine functional group of 1.94 molar equivalent of the 6-bromohexane amide to generate an amide-tertiary amine monomer with the following chemical structure:

[0033]

[0034] Step 3: Utilizing a nucleophilic substitution mechanism, a quaternization reaction occurs between the tertiary amine functional group of a 1 molar equivalent amide-based tertiary amine monomer and the chlorine functional group of a 1.15 molar equivalent epichlorohydrin monomer, generating an epoxide-ether-based amide-based quaternary ammonium salt end-capping agent. Its chemical structural formula is as follows:

[0035]

[0036] The specific experimental steps for preparing epoxidized ether-amide quaternary ammonium salt end-capping agents are as follows:

[0037] Under nitrogen protection, 2.2 g of 4,7,10-trioxo-1,13-tridecanediamine and 50 mL of N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 10 mL of N,N-dimethylformamide solution containing 1.4 g of ethylene glycol monomethyl ether propionic acid and 5 mL of N,N-dimethylformamide solution containing 0.8 g of N,N'-dicyclohexylcarbodiimide catalyst were added to the three-necked flask in sequence. The mixture was heated to 80 °C and stirred for 5 h. After cooling to room temperature, the solvent was removed by rotary evaporation, washed with dichloromethane, and dried under vacuum to obtain the amide-amino monomer.

[0038] 1.8 g of amide-amino monomer and 30 mL of N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 20 mL of N,N-dimethylformamide solution containing 1.9 g of 6-bromohexaneamide and 1.2 mL of triethylamine catalyst were added to the three-necked flask in sequence. The mixture was heated to 70 °C and stirred for 6 h. After cooling to room temperature, the solvent was removed by rotary evaporation. The mixture was washed with dichloromethane and dried under vacuum to obtain the amide-tertiary amine monomer.

[0039] 1.9 g of amide-based tertiary amine monomer and 20 mL of N,N-dimethylformamide were added to a three-necked flask and stirred at room temperature until completely dissolved. Then, 0.3 mL of epichlorohydrin was added to the three-necked flask. Under nitrogen protection and mechanical stirring, the mixture was heated to 40 °C and stirred for 12 h. After cooling to room temperature, the solvent was removed by rotary evaporation. The mixture was washed with dichloromethane and dried under vacuum to obtain an epoxide-based amide-based quaternary ammonium salt end-capping agent.

[0040] The 1H NMR characterization of the epoxide ether-amide quaternary ammonium salt end-capping agent is as follows: 1 HNMR (DMSO-d6, 400MHz) δ: 1.49-1.63 (m, 12H), 1.80-1.87 (m, 2H), 1.99-2.06 (m, 2H), 2.19-2.23 (t, 4H), 2.46-2.50 (t, 2H), 3.12-3. 17 (m, 2H), 3.36 (s, 3H), 3.44-3.64 (m, 26H), 3.80-3.84 (t, 2H), 3.95-4.02 (m, 1H), 6.69 (s, 4H, -CONH2), 7.51-7.54 (t, 1H, -CONH-).

[0041] Example 2:

[0042] Preparation of modified polyethylene terephthalate (PET-I) with flexible, hygroscopic, and antistatic functions: 10 parts by weight of polyethylene terephthalate (PET) were modified by end-capping with 0.5 parts by weight of an epoxy ether-amide quaternary ammonium salt type end-capping agent. The modified PET-I was obtained by ring-opening reaction between the epoxy functional groups of the epoxy ether-amide quaternary ammonium salt type end-capping agent and the terminal hydroxyl or carboxyl functional groups on the main chain of polyethylene terephthalate. The specific experimental steps were as follows: 100 mL of anhydrous N-methyl... Pyrrolidone was added to a three-necked flask, and the temperature was raised to 150°C. 10g of polyethylene terephthalate (brand name 545) was added and stirred until completely dissolved. The temperature was lowered to 70°C, and under nitrogen protection, 10mL of anhydrous N-methylpyrrolidone solution containing 0.5g of epoxide ether-amide quaternary ammonium salt end-capping agent was slowly added to the three-necked flask. The mixture was stirred at 70°C for 6 hours. After cooling to room temperature, the solvent was removed by rotary evaporation at 40mbar and 50°C using a vacuum pump. The product was then vacuum dried to obtain modified polyethylene terephthalate PET-I.

[0043] Example 3:

[0044] Preparation of modified polyethylene terephthalate (PET-II) with flexible, hygroscopic, and antistatic functions: 10 parts by weight of polyethylene terephthalate (PET) were modified by end-capping with 1.0 parts by weight of an epoxy ether-amide quaternary ammonium salt type end-capping agent. The modified PET-II was obtained by ring-opening reaction between the epoxy functional groups of the epoxy ether-amide quaternary ammonium salt type end-capping agent and the terminal hydroxyl or carboxyl functional groups on the main chain of PET. The specific experimental steps were the same as those for the preparation of modified polyethylene terephthalate (PET-I), with the only difference being that the amount of epoxy ether-amide quaternary ammonium salt type end-capping agent used was 1.0 g.

[0045] Example 4:

[0046] Preparation of modified polyethylene terephthalate (PET-III) with flexible, hygroscopic, and antistatic functions: 10 parts by weight of polyethylene terephthalate (PET) were modified by end-capping with 1.5 parts by weight of an epoxy ether-amide quaternary ammonium salt type end-capping agent. The modified PET-III was obtained by ring-opening reaction between the epoxy functional groups of the epoxy ether-amide quaternary ammonium salt type end-capping agent and the terminal hydroxyl or carboxyl functional groups on the main chain of PET. The specific experimental steps were the same as those for the preparation of modified PET-I, with the only difference being that the amount of epoxy ether-amide quaternary ammonium salt type end-capping agent used was 1.5 g.

[0047] Example 5:

[0048] Preparation of imitation acetate polyester fiber: First, the modified polyethylene terephthalate (PET) was cut into rectangular modified PET chips with a thickness of 3 mm and a length of 10 mm using a slicing machine. After drying the modified PET chips at 120℃ for 12 h, they were fed into a melt spinning machine for melt spinning and then stretched by a parallel drawing machine to obtain imitation acetate polyester fiber with a fineness of 150 dtex.

[0049] The fineness of the imitation acetate polyester fiber was tested according to GB / T 14343-2008 "Test Method for Linear Density of Chemical Fiber Filaments";

[0050] The process parameters for the melt spinning machine are set as follows: the temperatures of the screw zones 1-4 are 230℃, 250℃, 250℃, and 255℃, respectively; the rotation speed is 50 r / min; the screw diameter is 25 mm; the length-to-diameter ratio is 28; the temperature of the metering pump, the bend pipe, and the housing is 260℃; and the spinning speed is 800 m / min.

[0051] The process parameters of the parallel drawing machine are set as follows: drawing speed is 200m / min, drawing ratio is 3.5 times, and the hot plate temperature is controlled at 60℃ and 130℃ during drawing.

[0052] Modified polyethylene terephthalate (PET) is one of PET-I, PET-II, and PET-III;

[0053] When the modified polyethylene terephthalate (PET) is PET-I, the resulting fiber product is denoted as imitation acetate polyester fiber I.

[0054] When the modified polyethylene terephthalate (PET) is PET-II, the resulting fiber product is denoted as imitation acetate polyester fiber II.

[0055] When the modified polyethylene terephthalate (PET) is PET-III, the resulting fiber product is denoted as imitation acetate polyester fiber III.

[0056] Comparative example:

[0057] Preparation of conventional polyester fibers: First, polyethylene terephthalate (brand name 545) is cut into rectangular polyethylene terephthalate slices with a thickness of 3 mm and a length of 10 mm using a slicing machine. After drying the polyethylene terephthalate slices at 120℃ for 12 h, they are fed into a melt spinning machine for melt spinning and then drawn through a parallel drawing machine to obtain conventional polyester fibers with a fineness of 150 dtex.

[0058] The fineness of conventional polyester fibers was tested according to GB / T 14343-2008 "Test Method for Linear Density of Chemical Fiber Filaments";

[0059] The process parameters for the melt spinning machine are set as follows: the temperatures of the screw zones 1-4 are 260℃, 280℃, 280℃, and 285℃, respectively; the rotation speed is 50 r / min; the screw diameter is 25 mm; the length-to-diameter ratio is 28; the temperature of the metering pump, the bend pipe, and the housing is 290℃; and the spinning speed is 800 m / min.

[0060] The process parameters of the parallel drawing machine are set as follows: drawing speed 200m / min, drawing ratio 3.5 times, hot plate temperature controlled at 80℃ and hot plate temperature controlled at 150℃ during drawing.

[0061] Performance testing:

[0062] (1) Moisture regain test: The moisture regain of the sample was tested according to GB / T 6503-2017 "Test Method for Moisture Regain of Chemical Fibers". The moisture regain of the sample is used to characterize its moisture regain performance. The higher the moisture regain, the better the moisture regain performance. The specific test steps are as follows: After placing the sample under constant temperature and humidity (temperature 20℃, relative humidity 65%) for 48h, it was placed in an eight-basket drying oven and weighed. The mass at this time was recorded as m0g. After drying at 100℃ to constant weight (the interval between two weighings is 10min and the mass difference between the two weighings is less than 0.05% of the second mass), it was weighed again and the mass at this time was recorded as mg. The moisture regain of the sample was calculated. The specific calculation method is as follows:

[0063] Moisture regain (%) = (m0 - m) / m × 100%;

[0064] (2) Softness test: The fiber sample was made into a plain weave fabric with warp and weft directions using a loom. The bending stiffness of the fiber textile was tested according to GB / T 18318.1-2009 "Determination of bending properties of textiles - Part 1: Inclined plane method". The bending stiffness of the fiber textile was used to characterize its softness. The smaller the bending stiffness, the softer the fiber sample.

[0065] (3) Antistatic performance test: The volume resistivity of the sample was tested according to GB / T 14342-2015 "Test method for resistivity of short chemical fiber". The antistatic performance of the sample was characterized by the volume resistivity of the fiber. The smaller the volume resistivity, the better the antistatic performance.

[0066] (4) Mechanical property test: The breaking strength of the sample was tested in accordance with GB / T 14344-2022 "Test method for tensile properties of chemical fiber filaments" to characterize its mechanical properties.

[0067] The results of the above performance tests are shown in Table 1 below.

[0068] Table 1. Experimental results of the performance of imitation acetate polyester fiber

[0069]

[0070] A comprehensive analysis of the above experimental results leads to the following conclusions:

[0071] Conclusion 1: This invention utilizes an epoxide-ether-based amide-based quaternary ammonium salt end-capping agent to modify polyethylene terephthalate. The resulting polyester fiber exhibits significantly increased moisture regain, significantly reduced bending stiffness and volume resistivity. Compared to unmodified conventional polyester fiber, it achieves significant improvements in moisture absorption, softness, and antistatic properties.

[0072] Conclusion 2: The acetate-like polyester fiber prepared by this invention has a soft touch similar to that of acetate fiber, as well as good moisture absorption and antistatic properties, while also retaining good breaking strength (significantly greater than that of acetate fiber).

Claims

1. A preparation process for imitation acetate polyester fiber, characterized in that, Includes the following steps: Step 1: Prepare an epoxide ether-amide quaternary ammonium salt type end-capping agent with the following chemical structural formula: Step 2: The epoxy functional groups of the epoxide ether-amide quaternary ammonium salt end-capping agent undergo a ring-opening reaction with the terminal hydroxyl or terminal carboxyl functional groups on the main chain of polyethylene terephthalate (PET) to complete the end-capping modification of PET and obtain a modified PET with flexible, hygroscopic and antistatic functions. Step 3: Using the modified polyethylene terephthalate (PET) as raw material, imitation acetate polyester fiber is obtained through melt spinning and parallel drawing processes.

2. The preparation process of the imitation acetate polyester fiber according to claim 1, characterized in that, The preparation method of the epoxide ether-amide quaternary ammonium salt type capping agent is as follows: Using 4,7,10-trioxo-1,13-tridecanediamine as a raw material, an amidation reaction is carried out between the -NH2 functional group of 1 molar equivalent of 4,7,10-trioxo-1,13-tridecanediamine and the carboxyl functional group of 0.91-0.99 molar equivalent of ethylene glycol monomethyl ether propionic acid to generate an amide amino monomer. A nucleophilic substitution reaction is carried out between the -NH2 functional group of 1 molar equivalent of an amide amino monomer and the bromine functional group of 1.91-1.99 molar equivalent of 6-bromohexane amide to generate an amide tertiary amine monomer. By utilizing a nucleophilic substitution reaction mechanism, a quaternization reaction occurs between the tertiary amine functional group of a 1 molar equivalent amide-based tertiary amine monomer and the chlorine functional group of 1.1-1.2 molar equivalent epichlorohydrin, generating an epoxide ether-based amide-based quaternary ammonium salt end-capping agent.

3. The preparation process of the imitation acetate polyester fiber according to claim 1, characterized in that, The amount of the epoxide ether amide quaternary ammonium salt end-capping agent in the modified polyethylene terephthalate (PET) is 5-15 wt% of the amount of polyethylene terephthalate.

4. The preparation process of the imitation acetate polyester fiber according to claim 1, characterized in that, The process parameters for the melt spinning process are set as follows: the temperatures of the screw zones 1-4 are 220-230℃, 240-255℃, 240-260℃, and 250-260℃, respectively; the temperatures of the metering pump, the bend pipe, and the housing are all 255-260℃; and the spinning speed is 600-900m / min.

5. The preparation process of the imitation acetate polyester fiber according to claim 1, characterized in that, The process parameters for the parallel drawing process are set as follows: drawing speed is 100-300 m / min, drawing ratio is 3-5 times, and the temperature of the hot plate is controlled at 50-70℃ and the temperature of the hot plate is controlled at 120-140℃ during drawing.

6. A polyester-acetate-like fiber prepared according to any one of claims 1-5, characterized in that, The fineness of the imitation acetate polyester fiber is 120-180 dtex.

7. The imitation acetate polyester fiber according to claim 6, characterized in that, The moisture regain of the imitation acetate polyester fiber is (1.6-2.3)%.

8. The imitation acetate polyester fiber according to claim 6, characterized in that, The volume resistivity of the imitation acetate polyester fiber is (10) 8 -10 9 )Ω·cm.

9. A polyester-acetate-like fiber prepared according to any one of claims 1-5, characterized in that, The application of the aforementioned imitation acetate polyester fiber in the textile field.

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