Alkali decrement process of polyester fabric

Abstract

The invention relates to the technical field of textile dyeing and finishing processing, in particular to an alkali deweighting process of a polyester fabric, which comprises the following steps: S1, dissolving sodium hydroxide or potassium hydroxide with the mass concentration of 2-5g / L, an auxiliary agent with the mass concentration of 0.1-0.3 g / L, and an accelerant in water to obtain an alkali liquor with the mass concentration of 2-5g / L, the mass concentration of 0.1-0.3 g / L and the mass concentration of 0.1-0.3 g / L; the amount-of-substance concentration of the accelerant ranges from 0.03 mmol / L to 0.06 mmol / L; the auxiliary agent is a penetrant, and the penetrant is alkyl glycoside grafted hydroxyl-terminated hyperbranched polyester; s2, the polyester fabric is put into alkali liquor according to the bath ratio of 1: (15-25), then the temperature is increased to 80-90 DEG C, heat preservation is conducted for 25-45 min, and then the polyester fabric is taken out, washed with water and dried; the method has the advantages that the decrement rate of the polyester fabric is ensured, and the strength of the polyester fabric after alkali decrement treatment is improved.

Description

Technical Field

[0001] The present application relates to the technical field of textile dyeing and finishing, and in particular to an alkali reduction process for polyester fabrics. Background Art

[0002] The alkali reduction process of polyester fabric is to use alkali to hydrolyze polyester (polyester) fiber to make its surface smooth, reduce weight, make the fabric thinner, and make it soft, so that it has a silk-like feel and luster. Therefore, it is also called polyester imitation silk processing technology. After the alkali reduction is completed, the polyester fabric needs to be acid neutralized to remove the residual caustic soda on the surface of the fabric, and then high-temperature and high-pressure disperse dyeing is carried out. Because the conventional disperse dyes used for polyester fabric dyeing contain hydroxyl, amino, ester, amide, cyano and other groups, when dyeing at high temperature and high pressure, too high or too low pH of the dye solution will cause dye hydrolysis or color change, so the pH value needs to be controlled in the range of 5-6. After dyeing, polyester fabrics usually need reduction cleaning to remove floating colors on the surface of the fabric and oligomers precipitated during the dyeing process.

[0003] However, due to the effect of surface tension, the yarn inside the polyester fabric is insufficiently in contact with the caustic soda. In order to obtain a good alkali reduction effect, a larger amount of caustic soda needs to be added. Increasing the amount of caustic soda can easily cause uneven yarn thickness of the polyester fabric, resulting in insufficient strength of the polyester fabric, which is not conducive to the quality of the polyester fabric. Summary of the invention

[0004] In order to ensure the weight reduction rate of polyester fabric and improve the strength of polyester fabric after alkali weight reduction treatment, the present application provides an alkali weight reduction process for polyester fabric.

[0005] The present application provides an alkali reduction process for polyester fabrics, which adopts the following technical scheme: An alkali reduction process for polyester fabrics comprises the following steps: S1. Prepare alkali solution Dissolve sodium hydroxide or potassium hydroxide, an auxiliary agent and a promoter in water to obtain an alkaline solution, wherein the mass concentration of sodium hydroxide or potassium hydroxide is 2-5 g / L, the mass concentration of the auxiliary agent is 0.1-0.3 g / L, and the molar concentration of the promoter is 0.03-0.06 mmol / L; the auxiliary agent is a penetrant, and the penetrant is an alkyl glycoside grafted terminal hydroxyl hyperbranched polyester; S2. Alkali reduction treatment Put the polyester fabric into the alkali solution with a bath ratio of 1:(15-25), then heat it to 80-90℃, keep it warm for 25-45min, then take out the polyester fabric, wash it with water, and dry it.

[0006] By adopting the above technical scheme, a penetrant is added to the alkali solution, and the penetrant can reduce the interfacial tension between the polyester fabric fiber and the alkali solution, so that the fabric fiber is fully in contact with the alkali solution, and the fabric fiber inside can also fully react with the sodium hydroxide in the alkali solution, so that the polyester fabric fiber is uniformly hydrolyzed, not only the reduction rate is improved under the condition of sodium hydroxide and other concentrations, but also the strength of the polyester fabric after alkali reduction treatment is improved, and the quality of the polyester fabric after alkali reduction treatment is greatly improved; on this basis, the inventors of the present application believe that the solubility, foaming property, molecular viscosity, etc. of the penetrant can affect the permeability of the penetrant. From this perspective, the inventors of the present application have greatly improved the permeability of the alkyl polyglycoside by grafting the alkyl polyglycoside with the terminal hydroxyl hyperbranched polyester, and using the advantages of the hyperbranched polymer that is very easy to dissolve in water and has very low molecular viscosity, and by grafting the terminal hydroxyl hyperbranched polymer, it is found that the foaming property of the alkyl polyglycoside is greatly reduced, thereby reducing the reduction of the foaming on the polyester fiber surface caused by the alkyl polyglycoside and the reduction of the hydrolysis caused by the contact with sodium hydroxide. It is also found that by grafting alkyl polyglycoside with terminal hydroxyl hyperbranched polyester, the molecular volume is increased, the distance between fibers can be expanded to a certain extent, thereby further increasing the contact area between the fibers and sodium hydroxide, and the hydrolysis effect is better. In summary, the present application mainly improves the uniformity of hydrolysis of polyester fabric fibers by improving the permeability of the penetrant, thereby improving the weight reduction rate of polyester fabric and the strength after alkali weight reduction treatment.

[0007] Preferably, the penetrant is obtained by esterifying an alkyl glycoside with a dicarboxylic acid, and then reacting the obtained intermediate product with a terminal hydroxyl hyperbranched polyester.

[0008] By adopting the above technical scheme, the dicarboxylic acid is used as a bridge to connect the alkyl glycoside and the terminal hydroxyl hyperbranched polyester, so as to obtain the penetrant.

[0009] Preferably, the molecular weight of the terminal hydroxyl hyperbranched polyester is 600-2600.

[0010] By adopting the above technical solution, as the molecular weight of the terminal hydroxyl hyperbranched polyester increases, its reduction rate gradually decreases, and its warp strength and weft strength also gradually decrease. It is considered that because its molecular weight is too large, on the one hand, the penetrant is not easy to enter the interior of the fabric due to its large volume, and on the other hand, its molecular weight gradually increases, and it is not easy to play the role of the alkyl polyglycoside penetrant. Therefore, the molecular weight of the terminal hydroxyl hyperbranched polyester should not be too large.

[0011] Preferably, the dicarboxylic acid is one or more of succinic acid, maleic acid and phthalic acid.

[0012] By adopting the above technical scheme, any of the dicarboxylic acids can be used. If a dicarboxylic acid with a longer carbon chain is used, the reaction steric hindrance is reduced, resulting in the carboxylic acid groups on the dicarboxylic acid reacting with the alkyl glycoside but not being able to be grafted with the terminal hydroxyl hyperbranched polyester.

[0013] Preferably, the alkyl glycoside is one or more of APG0810, APG0814 and APG1214.

[0014] By adopting the above technical solution, the alkyl glycosides can be of the following types, which are not listed one by one in the embodiments, but in theory all of them can be used.

[0015] Preferably, the auxiliary agent further comprises a nonionic surfactant, and the mass concentration ratio of the penetrant and the nonionic surfactant is 1:(0.5-2).

[0016] By adopting the above technical solution, the non-ionic surfactant is added to the auxiliary agent, which can play a synergistic role with the penetrant, thereby making the penetration effect better.

[0017] Preferably, the auxiliary agent further comprises polyvinyl pyrrolidone, and the mass concentration ratio of the penetrant, the nonionic surfactant and the polyvinyl pyrrolidone is 1:(0.5-2):(0.03-0.07).

[0018] By adopting the above technical solution, polyvinyl pyrrolidone has a strong affinity with polyester fibers. By adding polyvinyl pyrrolidone to the auxiliary agent, the dyeing power and hydrophilicity can be improved, thereby reducing the interfacial tension between the polyester fiber and the alkali solution. In addition, polyvinyl pyrrolidone has a strong affinity with polyester fibers, which can play an introduction role, improve the penetration of penetrants and non-ionic surfactants into the internal fibers of polyester fabrics, thereby improving the hydrolysis uniformity. Through the synergistic effect of the three, the quality of polyester fabrics after alkali reduction treatment is greatly improved.

[0019] Preferably, the average molecular weight of the polyvinyl pyrrolidone is 3500.

[0020] By adopting the above technical solution, as the molecular weight of polyvinyl pyrrolidone increases, its molecular viscosity gradually increases, which is not conducive to its penetration. Therefore, its molecular weight should not be too large. When its molecular weight is large, it will prevent the penetration of penetrants and non-ionic surfactants, thereby reducing the hydrolysis of fibers inside the polyester fabric.

[0021] Preferably, the mass concentration ratio of the penetrant, the nonionic surfactant and the polyvinyl pyrrolidone is 1:1:0.05.

[0022] By adopting the above technical solution, the synergistic effect of the three is optimal at this ratio.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. By grafting alkyl polyglycoside with terminal hydroxyl hyperbranched polyester, the permeability of alkyl polyglycoside is greatly improved by utilizing the advantages of hyperbranched polymers being very easy to dissolve in water and having very low molecular viscosity. In addition, by grafting terminal hydroxyl hyperbranched polymers, it is found that the foaming property of alkyl polyglycoside is greatly reduced, thereby reducing the foaming on the surface of polyester fibers caused by alkyl polyglycoside and the reduction of hydrolysis caused by contact with sodium hydroxide. It is also found that by grafting alkyl polyglycoside with terminal hydroxyl hyperbranched polyester, the molecular volume is increased, the distance between fibers can be expanded to a certain extent, thereby further increasing the contact area between fibers and sodium hydroxide, and achieving a better hydrolysis effect.

[0024] 2. Polyvinyl pyrrolidone has a strong affinity with polyester fibers. Adding polyvinyl pyrrolidone to the additives can improve dyeing power and hydrophilicity, thereby reducing the interfacial tension between polyester fibers and alkali solutions. Polyvinyl pyrrolidone has a strong affinity with polyester fibers, and it can play an introduction role, improving the penetration of penetrants and non-ionic surfactants into the internal fibers of polyester fabrics, thereby improving the uniformity of hydrolysis. Through the synergistic effect of the three, the quality of polyester fabrics after alkali reduction treatment is greatly improved.

[0025] 3. The polyester fabric was subjected to alkali reduction treatment by the alkali reduction process for polyester fabric of the present application. Under the condition that the mass concentration of sodium hydroxide was 2.5 g / L, the reduction rate of the polyester fabric could reach 15.3%, and the highest could reach 16.9%. Moreover, the warp strength of the polyester fabric after alkali reduction treatment could reach a maximum of 459 N, and the weft strength could reach a maximum of 687 N. This indicates that the alkali reduction process of the present application can make the fibers of the polyester fabric hydrolyzed more evenly, and greatly reduce the strength reduction of the polyester fabric caused by excessively thin fibers due to the large surface tension of the internal fibers, insufficient reaction with the alkali solution, and excessive external consumption of sodium hydroxide. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with the specific contents.

[0027] raw material The raw materials in the preparation examples and embodiments of the present application were all purchased from commercial sources.

[0028] Preparation Example Preparation Example 1 A penetrant, the preparation method of which is as follows: S1. In a nitrogen atmosphere, 5 g of alkyl polyglucoside was added to 200 g of DMF, 20 g of toluene was added as a water-carrying agent, 0.2 g of p-toluenesulfonic acid was added as a catalyst, and the mixture was stirred until dissolved. The mixture was then heated to 150° C., and 2.4 g of maleic acid was added. The mixture was stirred for 16 h, and the solvent was removed by distillation under reduced pressure to obtain alkyl polyglucoside grafted with maleic acid. The alkyl polyglucoside was APG0810. S2. Under nitrogen atmosphere, 11 g of terminal hydroxyl hyperbranched polyester was added to 200 g of DMF. The model of terminal hydroxyl hyperbranched polyester was HyPer H201, with a molecular weight of 600 and a hydroxyl number of 5-7 / mol. 20 g of toluene was added as a water-carrying agent, and then 0.2 g of p-toluenesulfonic acid was added as a catalyst. The temperature was raised to 150° C., and then the alkyl glycoside grafted maleic acid of S1 was added. The alkyl glycoside grafted maleic acid was added three times with an interval of 2 hours. After the addition was completed, stirring was continued for 13 hours. The solvent was removed by distillation under reduced pressure to obtain the alkyl glycoside grafted terminal hydroxyl hyperbranched polyester, i.e., the penetrant.

[0029] Preparation Example 2 A penetrant, which is different from Preparation Example 1 in that the added amount of the terminal hydroxyl hyperbranched polyester is 22 g, the molecular weight is 1200, the number of hydroxyl groups is 10-12 / mol, and the remaining steps are the same as those of the Preparation Example.

[0030] Preparation Example 3 A penetrant, which is different from Preparation Example 1 in that the added amount of the terminal hydroxyl hyperbranched polyester is 47 g, the molecular weight is 2600, the number of hydroxyl groups is 20-24 / mol, and the remaining steps are the same as those of the Preparation Example. Example

[0031] Example 1 An alkali reduction process for polyester fabrics comprises the following steps: S1. Prepare alkali solution Sodium hydroxide, auxiliary agent and accelerator are dissolved in water to obtain alkali solution, wherein the mass concentration of sodium hydroxide is 2.5 g / L, the mass concentration of auxiliary agent is 0.2 g / L, the model of accelerator is 1227, and the molar concentration of accelerator is 4.5×10 -5 mol / L; wherein the auxiliary agent is a penetrant, and the penetrant is from Preparation Example 1; S2. Alkali reduction treatment Put the polyester fabric into the alkali solution with a bath ratio of 1:20, then heat it to 85°C at a heating rate of 2°C / min, and then keep it warm for 30 minutes. After the insulation is completed, take the polyester fabric out of the alkali solution, wash it twice with tap water, and then dry it.

[0032] Example 2 An alkali reduction process for polyester fabric is different from Example 1 in that the penetrant comes from Preparation Example 2, and the remaining steps are the same as those of Example 1.

[0033] Example 3 An alkali reduction process for polyester fabric is different from Example 1 in that the penetrant comes from Preparation Example 3, and the remaining steps are the same as Example 1.

[0034] Example 4 An alkali reduction process for polyester fabric, which is different from Example 1 in that the auxiliary agent in the alkali solution is a mixture of a penetrant and a non-ionic surfactant, the mass concentration ratio of the penetrant and the non-ionic surfactant added is 1:1, the non-ionic surfactant is fatty alcohol polyoxyethylene ether AEO-9, and the remaining steps are the same as Example 1.

[0035] Example 5 An alkali reduction process for polyester fabric is different from Example 4 in that the mass concentration ratio of the added penetrant and non-ionic surfactant is 1:0.5, and the remaining steps are the same as Example 4.

[0036] Example 6 An alkali reduction process for polyester fabric is different from Example 4 in that the mass concentration ratio of the added penetrant and non-ionic surfactant is 1:2, and the remaining steps are the same as Example 4.

[0037] Example 7 A alkali reduction process for polyester fabric, which is different from Example 4 in that the auxiliary agent also includes polyvinyl pyrrolidone, the mass concentration ratio of the penetrant, the non-ionic surfactant and the polyvinyl pyrrolidone added is 1:1:0.03, the molecular weight of the polyvinyl pyrrolidone is 3500, and the corresponding specification is K12, and the remaining steps are the same as Example 4.

[0038] Example 8 A polyester fabric alkali reduction process is different from Example 4 in that the auxiliary agent also includes polyvinyl pyrrolidone, the mass concentration ratio of the penetrant, the nonionic surfactant and the polyvinyl pyrrolidone added is 1:1:0.05, and the remaining steps are the same as Example 4.

[0039] Example 9 A polyester fabric alkali reduction process is different from Example 4 in that the auxiliary agent also includes polyvinyl pyrrolidone, the mass concentration ratio of the penetrant, the nonionic surfactant and the polyvinyl pyrrolidone added is 1:1:0.07, and the remaining steps are the same as Example 4.

[0040] Comparative Example Comparative Example 1 An alkali reduction process for polyester fabric is different from that in Example 1 in that no penetrant is added to the alkali solution, and the remaining steps are the same as those in Example 1.

[0041] Comparative Example 2 An alkali reduction process for polyester fabric is different from that in Example 1 in that the penetrant added to the alkali solution is alkyl glycoside, and the remaining steps are the same as those in Example 1.

[0042] Comparative Example 3 An alkali reduction process for polyester fabric is different from that of Example 7 in that the molecular weight of the polyvinyl pyrrolidone added to the alkali solution is 5500, and the corresponding product specification is K15, and the remaining steps are the same as those of Example 7.

[0043] Performance testing Detection method / test method The same batch of polyester fabrics were subjected to alkali reduction treatment according to the alkali reduction processes of Examples 1-9 and Comparative Examples 1-3, and then tested according to the following testing method. The test results are shown in Table 1.

[0044] Reduction rate: The samples after alkali reduction treatment were dried in a 9053A electric constant temperature blast drying oven (Shanghai Yuejin Medical Device Factory) at 60 °C, then heated to 105 °C for 4 h, and then quickly weighed on an electronic balance. The reduction rate was calculated according to formula (1), where W0 and W1 are the absolute dry weights of the samples before and after treatment, respectively; Reduction rate = (W0-W1) / W0×100% (1) 2) Determination of breaking strength: According to GB / T3923.1-2013 "Tensile properties of textile fabrics Part 1: Determination of breaking strength and elongation at break (strip method)", a T201 multi-functional strength tester is used to measure the warp and weft strength of the fabric.

[0045] Table 1 Test results of Examples 1-9 and Comparative Examples 1-3 It can be seen from Examples 1-9 and Comparative Examples 1-3, as well as the test data in Table 1, that the alkali reduction process for polyester fabric of the present application is used to perform alkali reduction treatment on the polyester fabric, and under the condition that the mass concentration of sodium hydroxide is 2.5 g / L, the reduction rate of the polyester fabric can reach 15.3%, and can reach a maximum of 16.9%, and the warp strength of the polyester fabric after the alkali reduction treatment can reach a maximum of 459 N, and the weft strength can reach a maximum of 687 N; this indicates that the alkali reduction process of the present application can make the fibers of the polyester fabric hydrolyzed more uniformly, and greatly reduce the strength reduction of the polyester fabric caused by excessively thin fibers due to the large surface tension of the internal fibers, insufficient reaction with the alkali solution, and excessive external consumption of sodium hydroxide.

[0046] Adding a penetrant to the alkali solution can reduce the interfacial tension between the polyester fabric fiber and the alkali solution, so that the fabric fiber is fully in contact with the alkali solution, so that the fabric fiber inside can also fully react with the sodium hydroxide in the alkali solution, so that the polyester fabric fiber is uniformly hydrolyzed, not only the reduction rate is improved under the condition of sodium hydroxide concentration, but also the strength of the polyester fabric after alkali reduction treatment is improved, and the quality of the polyester fabric after alkali reduction treatment is greatly improved. The test data of Example 1 and Comparative Example 1 can be verified. On this basis, the inventors of the present application believe that the solubility, foaming property, molecular viscosity, etc. of the penetrant can all affect the permeability of the penetrant. From this perspective, the inventors of the present application have greatly improved the permeability of the alkyl polyglycoside by grafting the alkyl polyglycoside with the terminal hydroxyl hyperbranched polyester, and utilizing the advantages of the hyperbranched polymer that is very easy to dissolve in water and has very low molecular viscosity, and by grafting the terminal hydroxyl hyperbranched polymer, it is found that the foaming property of the alkyl polyglycoside is greatly reduced, thereby reducing the reduction of the foaming on the polyester fiber surface caused by the alkyl polyglycoside and the reduction of the hydrolysis caused by contact with sodium hydroxide. It is also found that by grafting alkyl polyglycoside with terminal hydroxyl hyperbranched polyester, the molecular volume is increased, the distance between fibers can be expanded to a certain extent, thereby further increasing the contact area between the fibers and sodium hydroxide, and the hydrolysis effect is better. This can be verified by the test results of Example 1 and Comparative Example 2.

[0047] It can be seen from the test data of Examples 1-3 that as the molecular weight of the hydroxyl-terminated hyperbranched polyester increases, its reduction rate gradually decreases, and its warp strength and weft strength also gradually decrease. It is considered that because its molecular weight is too large, on the one hand, the penetrant is not easy to enter the fabric due to its large volume, and on the other hand, its molecular weight gradually increases, and it is not easy to play the role of the alkyl polyglycoside penetrant. Therefore, the molecular weight of the hydroxyl-terminated hyperbranched polyester should not be too large.

[0048] It can be seen from the test data of Examples 1 and 4-6 that the addition of nonionic surfactants to the additives can play a synergistic role with the penetrant, making its penetration effect better. By experimenting with the amount of nonionic surfactant added, it is found that the best mass concentration ratio of the penetrant to the nonionic surfactant is 1:1.

[0049] It can be seen from the test data of Example 4 and Examples 7-9 that polyvinyl pyrrolidone has a strong affinity with polyester fiber. By adding polyvinyl pyrrolidone to the auxiliary agent, the dyeing power and hydrophilicity can be improved, thereby reducing the interfacial tension between the polyester fiber and the alkali solution. In addition, polyvinyl pyrrolidone has a strong affinity with polyester fiber, which can play an introduction role, improve the penetration of the penetrant and non-ionic surfactant into the internal fibers of the polyester fabric, thereby improving the hydrolysis uniformity. Through the synergistic effect between the three, the quality of the polyester fabric after alkali reduction treatment is greatly improved.

[0050] However, as the molecular weight of polyvinyl pyrrolidone increases, its molecular viscosity gradually increases, which is not conducive to its penetration. Therefore, its molecular weight should not be too large. When its molecular weight is large, it prevents the penetration of penetrants and non-ionic surfactants, thereby reducing the hydrolysis of fibers inside the polyester fabric. This can be verified by the experimental data of Example 7 and Comparative Example 3.

[0051] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An alkali reduction process for polyester fabric, characterized in that: It includes the following steps: S1. Prepare alkali solution Dissolve sodium hydroxide or potassium hydroxide, an auxiliary agent and a promoter in water to obtain an alkaline solution, wherein the mass concentration of sodium hydroxide or potassium hydroxide is 2-5 g / L, the mass concentration of the auxiliary agent is 0.1-0.3 g / L, and the molar concentration of the promoter is 0.03-0.06 mmol / L; the auxiliary agent is a penetrant, and the penetrant is an alkyl glycoside grafted terminal hydroxyl hyperbranched polyester; S2. Alkali reduction treatment Put the polyester fabric into the alkali solution with a bath ratio of 1: (15-25), then heat it to 80-90℃, keep it warm for 25-45min, then take out the polyester fabric, wash it with water, and dry it.

2. The alkali reduction process for polyester fabric according to claim 1, characterized in that: The penetrant is obtained by esterification reaction of alkyl polyglycoside with dicarboxylic acid, and the obtained intermediate product is then esterified with terminal hydroxyl hyperbranched polyester.

3. The alkali reduction process for polyester fabric according to claim 2, characterized in that: The molecular weight of the terminal hydroxyl hyperbranched polyester is 600-2600.

4. The alkali reduction process for polyester fabric according to claim 2, characterized in that: The dicarboxylic acid is one or more of succinic acid, maleic acid and phthalic acid.

5. The alkali reduction process for polyester fabric according to claim 2, characterized in that: The alkyl glycoside is one or more of APG0810, APG0814 and APG1214.

6. The alkali reduction process for polyester fabric according to claim 1, characterized in that: The auxiliary agent also includes a nonionic surfactant, and the mass concentration ratio of the penetrant and the nonionic surfactant is 1: (0.5-2).

7. The alkali reduction process for polyester fabric according to claim 6, characterized in that: The auxiliary agent also includes polyvinyl pyrrolidone, and the mass concentration ratio of the penetrant, the nonionic surfactant and the polyvinyl pyrrolidone is 1: (0.5-2): (0.03-0.07).

8. The alkali reduction process for polyester fabric according to claim 7, characterized in that: The average molecular weight of the polyvinyl pyrrolidone is 3500.

9. The alkali reduction process for polyester fabric according to claim 8, characterized in that: The mass concentration ratio of the penetrant, the nonionic surfactant and the polyvinyl pyrrolidone is 1:1:0.05.

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