Polyester fiber modification method, oil-resistant polyester fiber and cotton clothing fabric

Abstract

The present application relates to the field of clothing fabrics, and discloses a polyester fiber modification method, oil-resistant polyester fiber, and cotton clothing fabric. The polyester fiber used in the fabric is subjected to a compound solution immersion cooling and freeze-thaw cycle treatment, and then immersed in the treatment liquid to load the effective ingredient, and then subjected to false twisting processing after drying. Through these three steps, a non-toxic and harmless oil-resistant ingredient that is incompatible with the fiber material and has a different processing temperature is stably loaded on the fiber surface, while ensuring the original strength index of the fiber, thereby obtaining a polyester fiber that is resistant to oil and has good strength, and thereby improving the oil-resistant contamination resistance of the cotton clothing fabric.

Description

Technical Field

[0001] The present invention relates to the field of clothing fabrics, in particular to a polyester fiber modification method, oil-resistant polyester fiber and cotton clothing fabrics. Background Art

[0002] Polyester fabric is a common clothing material woven from polyester fibers. Polyester fabric is wrinkle-resistant and possesses high strength and elasticity. However, due to the polyester fiber's surface affinity for oily substances, polyester fabric has a strong affinity for oil stains and easily absorbs them.

[0003] In autumn and winter, people's diet contains more oil, and cotton clothes made of polyester fabrics are easy to stick to oil stains, which makes it difficult to clean and takes a long time to dry the cotton clothes in the sun.

[0004] Among the current technologies for modifying polyester to obtain oil-resistant polyester materials, there is a method of adding polytetrafluoroethylene fluoride or other resin materials containing a high fluorine ratio into polyester to prepare fibers together. In this method, polytetrafluoroethylene fluoride or other resin materials containing a high fluorine ratio have poor compatibility with polyester. The poor compatibility can be improved and compensated by other methods when preparing particles or other large components. However, if the fibers are spun into fibers, due to compatibility issues, the fibers are easily broken during the spinning process and the spinning strength is poor, making them difficult to be applied in the field of clothing fabrics. Summary of the Invention

[0005] In order to reduce the oil stains on cotton clothes made of polyester fabrics and reduce the frequency of washing, a polyester fiber modification method, oil-resistant polyester fiber and cotton clothing fabric are provided. The polyester fiber is effectively modified to be oil-resistant without reducing the strength. The obtained oil-resistant polyester fiber component meets the requirements of the clothing field and is non-toxic and harmless. The woven fabric has good oil-resistant properties.

[0006] The first object of the present invention is achieved through the following technical solutions:

[0007] The modification method of polyester fiber comprises the following steps:

[0008] S1: soaking the original fiber in a sodium hydroxide / sodium chloride mixed solution, cooling it to below -4 to -6°C, maintaining the temperature for 1 hour, continuing to cool the solution, freezing it and then thawing it naturally, performing freeze-thaw cycles 3 to 4 times to obtain a treated fiber, wherein the sodium hydroxide concentration in the sodium hydroxide / sodium chloride mixed solution is 4 to 5.2 wt%, and the sodium chloride concentration is 2 to 5.2 wt%;

[0009] S2: soaking the primary treated fiber in a treatment solution for 3 hours, wherein the treatment solution includes chitosan, and the chitosan is dissolved in the treatment solution at a concentration of 5.7 to 8.3 wt %, to obtain a secondary treated fiber;

[0010] S3: After the secondary treated fiber is dried at room temperature, it is false twisted to obtain modified fiber.

[0011] By adopting the above technical solution, in step S1, the original fiber is first cooled to -4 to -6°C to reduce structural damage caused by sudden stress changes in the original fiber under rapid freezing and thawing. The original fiber is then kept immersed in the compound solution and subjected to freeze-thaw cycles, so that surface cracks are formed on the surface of the original fiber by ice crystal penetration. By controlling the number of freeze-thaw cycles, the surface cracks are small and numerous, and the original fiber body is not broken, with minimal strength reduction.

[0012] In step S2, the fiber is immersed in the treatment liquid, and the components including chitosan in the treatment liquid are loaded onto the surface of the fiber through the surface cracks formed in S1;

[0013] Then, the temperature is slowly restored naturally in S3, and false twisting is performed. In the false twisting process, the fiber is twisted and untwisted under pressure below the melting temperature of the fiber. In this process, the components including chitosan are strengthened and bonded to the fiber surface under the action of temperature and pressure of false twisting, and the damage to the internal structure of the fiber is repaired. At the same time, the mechanical changes of twisting and untwisting disperse the stress of the fiber, reduce the internal stress concentration of the fiber caused by multiple freeze-thaw cycles, and eliminate the fiber embrittlement caused by freeze-thaw cycles.

[0014] In summary, by carrying out the above three steps in sequence, non-toxic and harmless anti-oil components such as chitosan, which are incompatible with fiber materials and have different processing temperatures, are stably loaded on the fiber surface while ensuring the original strength indicators of the fiber, thereby obtaining a polyester fiber that is resistant to oil and has good strength.

[0015] Optionally, the concentration of sodium chloride in the sodium hydroxide / sodium chloride composite solution is half of the concentration of sodium hydroxide.

[0016] By adopting the above technical solution, sodium hydroxide provides an alkaline environment, causing a small amount of swelling of the surface of the polyester material at low temperatures, and then the sodium ions can penetrate the polyester material at low temperatures, thereby initiating the migration of moisture and anions, and then guiding ice crystals to penetrate the polyester material when the temperature continues to drop, forming cracks; in this regard, the sodium hydroxide concentration cannot be too high, otherwise it will cause the polyester material to swell too deeply or decompose, resulting in an irreversible or irreparable reduction in fiber strength.

[0017] On the one hand, sodium chloride lowers the freezing point of the compound solution, and on the other hand, it increases the sodium ion concentration in the compound solution, thereby improving the efficiency of crack generation at a higher concentration than sodium hydroxide. However, under the same alkaline conditions, excessive sodium ion concentration will cause the openings of tiny cracks to tear larger, causing excessive damage to the fiber surface and reducing the fiber strength. In addition, excessively large crack openings will reduce the specific surface area of ​​the fiber for the attachment of oil-proof components such as chitosan, which is not conducive to improving the oil-proof effect.

[0018] Based on the above research, the applicant compounded sodium hydroxide with a concentration twice that of sodium chloride, and the obtained fiber fabric achieved the best comprehensive oil-proof performance and fiber strength.

[0019] Optionally, the treatment liquid further comprises carboxymethyl cellulose, and the carboxymethyl cellulose accounts for 0.82 to 1.2 wt %.

[0020] By adopting the above technical solution, the carboxymethyl group on the carboxymethyl cellulose makes it have a good affinity with the surface of the polyester fiber, and the hydroxyl group on the carboxymethyl cellulose makes it have a good affinity with chitosan. The low concentration of carboxymethyl cellulose has almost no thickening effect on the treatment liquid, but at a low concentration of carboxymethyl cellulose, chitosan penetrates into the tiny cracks on the fiber surface more quickly. S2 obtains a higher chitosan loading within the same treatment time, thereby improving the oil-proof effect of the fiber and fiber fabric.

[0021] At the same time, after drying and losing water, the carboxymethyl cellulose in the tiny cracks adheres to the chitosan during the false twisting and pressing process, thereby strengthening the loading of the chitosan.

[0022] Optionally, when the original fiber is obtained by mixing terephthalic acid, ethylene glycol, pyromellitic anhydride ester, and a catalyst, melt granulating, and melt spinning, the false twist processing temperature is 183±2°C.

[0023] By adopting the above technical solution, the original fiber is produced with the raw materials including the above parts by mass. The obtained fiber and the prepared fabric have high surface gloss, good touch and excellent strength. The original fiber is false-twisted at 183±2°C, and the performance is well retained.

[0024] The second object of the present invention is achieved through the following technical solutions:

[0025] The oil-resistant polyester fiber is obtained by modifying the polyester fiber using the above-mentioned modification method.

[0026] By adopting the above technical solution, the polyester fiber has good strength and oil resistance, and the ingredients are non-toxic and harmless, meeting the requirements of the clothing field.

[0027] Optionally, the original fiber is obtained by mixing, melt granulating, and melt spinning the following raw materials in parts by mass: 100 parts of phthalic acid, 100 parts of ethylene glycol, and 4.2 parts of pyromellitic anhydride.

[0028] By adopting the above technical solution, the obtained fibers and the prepared fabrics have high surface gloss, good touch and excellent strength.

[0029] The third object of the present invention is achieved through the following technical solutions:

[0030] A cotton clothing fabric is obtained by weaving the above-mentioned oil-resistant polyester fiber.

[0031] By adopting the above technical solution, the cotton clothing fabric is resistant to oil stains and has good fiber strength.

[0032] In summary, this application has at least the following beneficial effects:

[0033] 1. Through three steps, chitosan and other non-toxic, incompatible, and temperature-sensitive oil-repellent ingredients are stably loaded onto the fiber surface while maintaining the fiber's original strength. This results in a polyester fiber that is oil-resistant and possesses excellent strength.

[0034] 2. The concentration of compound sodium hydroxide is twice that of sodium chloride, which improves the efficiency of crack generation and reduces damage to the fiber structure strength. The resulting fiber fabric has the best oil-proof performance and fiber strength.

[0035] 3. Adding a low concentration of carboxymethyl cellulose to the treatment liquid allows chitosan to penetrate into the tiny cracks on the fiber surface faster. S2 obtains a higher chitosan loading within the same treatment time, thereby improving the oil-proof effect of the fiber and fiber fabric. At the same time, after drying and water loss, the carboxymethyl cellulose in the tiny cracks adheres to the chitosan during the false twisting and pressurization process, thereby enhancing the chitosan loading. DETAILED DESCRIPTION

[0036] Preparation Example 1

[0037] A polyester fiber, the preparation method thereof has the following specific steps:

[0038] T1: Terephthalic acid, ethylene glycol, and pyromellitic anhydride were mixed in a molar ratio of 1:1.1:0.042, and then 22 ppm of antimony acetate (based on the mass of terephthalic acid) was added and mixed evenly. The mixture was subjected to an esterification reaction at 200°C and 0.50 MPa for 2 hours to obtain an esterification reaction material.

[0039] T2: Add 21% of the mass of the esterification reaction material to the hydroxyl-terminated polysiloxane, at 230°C, 0.043 MPa, for 1 hour; then at 248°C, 0.004 MPa, for 1.2 hours to obtain polyester;

[0040] T3: Spinning is performed to obtain polyester fibers, and the diameter of the polyester fibers is 16±2 μm.

[0041] Preparation Example 2

[0042] A polyester fiber, the preparation method thereof has the following specific steps:

[0043] T1: Terephthalic acid, ethylene glycol, and di-tert-butyl 5-vinyl isophthalate were mixed in a molar ratio of 1:1.1:0.038, and 18 ppm of ethylene glycol antimony (based on the mass of terephthalic acid) was added and mixed evenly. The mixture was then subjected to an esterification reaction at 180°C and 0.52 MPa for 2.2 hours to obtain an esterification reaction material.

[0044] T2: Add 21% of the mass of the esterification reaction material to the hydroxyl-terminated polysiloxane, at 220°C, 0.043 MPa, for 1.1 h; then at 240°C, 0.004 MPa, for 1.2 h to obtain polyester;

[0045] T3: Spinning is performed to obtain polyester fibers, and the diameter of the polyester fibers is 16±2 μm.

[0046] Example 1

[0047] An oil-resistant polyester fiber is obtained by modifying a polyester fiber as a raw fiber. In this embodiment, the polyester fiber obtained in Preparation Example 1 is used as the raw fiber. The modification method is as follows:

[0048] S1: The original fiber was immersed in a sodium hydroxide / sodium chloride mixed solution, cooled to below -4 to -6°C, maintained at the temperature for 1 hour, and the solution was further cooled, frozen and then thawed naturally, and the freeze-thaw cycle was performed 4 times. The sodium hydroxide concentration in the mixed solution was 5.2wt% and the sodium chloride concentration was 2.6wt%;

[0049] S2: Soak the treated fiber in the treatment solution for 3 hours to obtain secondary treated fiber.

[0050] The treatment liquid is a mixture of chitosan, carboxymethyl cellulose and water, wherein chitosan is dissolved in the treatment liquid with a concentration of 8 wt %, and carboxymethyl cellulose accounts for 0.82-1.2 wt % in the treatment liquid;

[0051] S3: After the secondary treated fiber is dried at room temperature, it is subjected to false twisting at a false twisting temperature of 183±2° C. to obtain modified fiber.

[0052] Comparative Example 1

[0053] A polyester fiber, which is the polyester fiber of Preparation Example 1.

[0054] Comparative Example 2

[0055] A polyester fiber is obtained by drying at room temperature through secondary treatment of the fiber obtained by the modification method S2 in Example 1.

[0056] Comparative Example 3

[0057] A polyester fiber is obtained by performing a false twisting process at a false twisting temperature of 183±2° C. after directly drying the fiber at room temperature by skipping step S2 and obtaining the once-treated fiber by the modification method S1 in Example 1.

[0058] Comparative Example 4

[0059] A polyester fiber is obtained by skipping step S1 and replacing the primary treated fiber with the polyester fiber of Preparation Example 1 according to the modification method of Example 1, and directly performing steps S2 and S3.

[0060] Comparative Example 5

[0061] A polyester fiber is similar to that of Example 1, except that the number of freeze-thaw cycles in S1 is 2.

[0062] Comparative Example 6

[0063] A polyester fiber is similar to that of Example 1, except that the number of freeze-thaw cycles in S1 is 5.

[0064] Examples 2 to 15

[0065] An oil-resistant polyester fiber is similar to Example 1, except that the raw material dosage or process parameters are different. The specific differences can be seen in Table 1 below.

[0066] Comparative Examples 7 to 9

[0067] An oil-resistant polyester fiber is similar to Example 1, except that the raw material dosage or process parameters are different. The specific differences can be seen in Table 1 below.

[0068] Table 1. Parameters of some raw materials and processes of Examples 1 to 5 and Comparative Examples 1 to 6

[0069]

[0070]

[0071] *Table 1 is used to show the differences between Examples 1 to 15 and Comparative Examples 1 to 9. For parameters of raw materials or processes not shown in Table 1, please refer to the description of each example.

[0072] The polyester fibers obtained in Examples 1 to 15 and Comparative Examples 1 to 9 are individually woven into fabrics through their warp and weft threads. For example, the polyester fibers of Example 1 are woven to obtain the cotton clothing fabric of Example 16, and the corresponding cotton clothing fabrics are obtained - Examples 16 to 30 and Comparative Examples 10 to 18.

[0073] The breaking strength of the polyester fibers of Examples 1 to 15 and Comparative Examples 1 to 9 was tested according to GB / T14344, and the oil resistance of the cotton fabrics of Examples 16 to 30 and Comparative Examples 10 to 18 was tested according to GB / T30159.1. The test results are shown in Table 2 below.

[0074] Table 2. Test results of Examples 1 to 30 and Comparative Examples 1 to 18

[0075]

[0076]

[0077] In combination with Table 1 and Table 2, by comparing Example 1, Comparative Example 1 and the corresponding fabric examples, it can be seen that the polyester fiber of Example 1 is processed in sequence according to S1 to S3 of the present application. Compared with Comparative Example 1 which has not undergone any treatment, the fiber strength and oil resistance of Example 1 are improved. The improvement in fiber strength is caused by the action of carboxymethyl cellulose and the false twist processing in S3, and the oil resistance is caused by the successful loading of the effective components of the treatment liquid in S2 of the present application on the surface of the polyester fiber.

[0078] Combined with comparative examples 2 to 3 and the corresponding fabric examples, the oil resistance of the polyester fiber is expected to be achieved in the present application. S1 to S3 are indispensable in the present application, among which step S2 is the key to improving the oil resistance, S1 is the prerequisite for the effect of S2, and S3 is the guarantee for significantly improving the oil resistance without reducing the fiber strength.

[0079] Comparing Examples 1 to 2, Comparative Examples 5 to 6 and the corresponding fabric examples, the freeze-thaw cycle number of S2 in this application should be 3 to 4 times. If the number of cycles is too small, as in Comparative Example 5, sufficient microcracks will not be generated for the effective ingredient loading in S2. If the number of cycles is too large, as in Comparative Example 6, the strength of the polyester fiber will be reduced and the effective ingredient loading stability in S2 will be poor.

[0080] In the present application, sodium hydroxide provides an alkaline environment, causing a small amount of swelling of the surface of the polyester material at low temperatures, and then sodium ions can penetrate the polyester material at low temperatures, thereby inducing cracks; while sodium chloride, on the one hand, lowers the freezing point of the composite solution, and on the other hand, increases the sodium ion concentration in the composite solution, thereby improving the efficiency of crack generation at a higher sodium hydroxide concentration.

[0081] However, under the same alkaline conditions, excessive sodium ion concentration can cause the opening of micro-cracks to tear larger, causing excessive damage to the fiber surface and reducing fiber strength. Excessively large crack openings can also reduce the specific surface area on the fiber for the attachment of oil-repellent ingredients such as chitosan, hindering the improvement of oil-repellent effects. In combination with Examples 1, 3-5, Comparative Example 7, and the corresponding fabric examples, the sodium chloride concentration in the compounded solution of this application is preferably half the concentration of sodium hydroxide.

[0082] In addition, the concentration of sodium hydroxide in the compound liquid of the present application should not be too high. If it is too high, the polyester material will swell too deeply or decompose, resulting in an irreversible or irreparable reduction in fiber strength. Combined with Example 2, Examples 6-7, Comparative Examples 8-9 and the corresponding fabric examples, it can be seen that the sodium hydroxide concentration in the present application is 4-5.2wt%, and the obtained oil-resistant polyester fiber has good strength and the obtained fabric has good oil resistance. When the sodium hydroxide concentration is greater than 5.2wt%, the strength of the polyester fiber decreases severely and the oil resistance of the fabric is weakened.

[0083] In combination with Example 2, Example 9 and the corresponding fabric examples, it can be seen that adding carboxymethyl cellulose to the treatment liquid in this application can better repair the strength of the obtained polyester fiber and the obtained fabric has better oil resistance.

[0084] In combination with Example 2, Examples 10 to 12 and the corresponding fabric examples, it can be seen that as the amount of carboxymethyl cellulose in the treatment liquid increases, the strength of the obtained polyester fiber gradually increases; the oil resistance of the obtained fabric first increases, and when the amount of carboxymethyl cellulose is 3.2wt%, the oil resistance decreases instead. This is because excessive use will thicken the treatment liquid, and the thickened treatment liquid is not easy to penetrate into the tiny cracks on the surface of the polyester fiber, which is not conducive to the improvement of the oil resistance. Therefore, the amount of carboxymethyl cellulose in the treatment liquid of this application is preferably 0.82 to 1.2wt%.

[0085] Combining Examples 2, 13-14, and the corresponding fabric examples, it can be seen that the false twisting temperature affects changes in fiber strength. In the present application, the false twisting temperature not only affects changes in polyester fiber strength, but also affects the stability of the loading of the oil-repellent active ingredient on the polyester fiber. When using Preparation Example 1 as the starting fiber, the false twisting temperature is preferably 183±2°C.

[0086] In combination with Example 15 and the corresponding fabric examples, it can be seen that the polyester fiber modification method of the present application can also be applied to polyester fibers other than those in Preparation Example 1, and the resulting fabric can have good oil resistance.

[0087] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for modifying polyester fiber, characterized in that: The following steps are included: S1: Soak the original fiber in a sodium hydroxide / sodium chloride solution, cool it to -4~-6℃, maintain the temperature for 1 hour, continue to cool the solution, freeze it and then thaw it naturally, perform freeze-thaw cycles 3~4 times to obtain a treated fiber. The sodium hydroxide / sodium chloride composite solution has a sodium hydroxide concentration of 4-5.2 wt %, and a sodium chloride concentration of 2-5.2 wt %. S2: soaking the primary treated fiber in a treatment solution for 3 hours, wherein the treatment solution includes chitosan and carboxymethyl cellulose, wherein the chitosan is dissolved in the treatment solution at a concentration of 5.7-8.3 wt %, and the carboxymethyl cellulose accounts for 0.82-1.2 wt %, to obtain a secondary treated fiber; S3: After the secondary treated fiber is dried at room temperature, it is false twisted to obtain modified fiber.

2. The polyester fiber modification method according to claim 1, characterized in that: The concentration of sodium chloride in the sodium hydroxide / sodium chloride composite solution is half of the concentration of sodium hydroxide.

3. The polyester fiber modification method according to claim 1, characterized in that: When the original fiber is obtained by mixing terephthalic acid, ethylene glycol, pyromellitic anhydride ester and a catalyst, melt granulating and melt spinning, the false twisting processing temperature is 183±2°C.

4. Oil-resistant polyester fiber, characterized by: The polyester fiber is obtained by modifying the polyester fiber according to any one of claims 1 to 3.

5. The polyester fiber according to claim 4, characterized in that The raw fiber is obtained by mixing the following raw materials in parts by mass, melt granulating, and melt spinning: 100 parts of terephthalic acid, 100 parts of ethylene glycol, and 4.2 parts of pyromellitic anhydride.

6. A cotton fabric, characterized by: The product is obtained by weaving the oil-resistant polyester fiber according to claim 4.

7. A cotton fabric, characterized by: The product is obtained by weaving the oil-resistant polyester fiber according to claim 5.

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