Method for removing oligomer on surface of polyester fiber product

Abstract

The invention discloses a method for removing oligomers on the surface of a polyester fiber product, which comprises the following steps: adding the polyester fiber product into water, adding 0.1-10g of nonionic surfactant with the HLB (Hydrophile-Lipophile Balance) value of less than 10 according to 1L of water, cleaning for 5-30 minutes at 15-60 DEG C, then discharging liquid, adding the polyester fiber product into a non-aqueous medium, cleaning for 5-15 minutes at 15-50 DEG C, then discharging liquid, washing for 5-15 minutes at 15-50 DEG C, and drying to obtain the polyester fiber product. The non-aqueous medium is selected from at least one of tetrachloroethylene, n-butyl acetate, gamma-butyrolactone, epsilon-caprolactone and 1, 4-dioxane; and taking out the cleaned polyester fiber product, and putting the polyester fiber product into a dryer provided with a condensation recovery device for sealed drying. Experiments prove that the method not only can effectively remove the oligomer on the surface of the polyester fiber product, but also is simple to operate and easy to realize large-scale production, and has the advantages of low cost, high efficiency, environmental protection and the like, and the waste liquid can be recycled.

Description

Technical Field

[0001] The invention relates to a method for removing oligomers on the surface of polyester fiber products, belonging to the technical field of chemical treatment. Background Art

[0002] Polyester fiber is the most consumed synthetic fiber in the world today. The basic component of polyester is polyethylene terephthalate, also known as polyester fiber (PET). Oligomers are by-products produced by the polycondensation of terephthalic acid and ethylene glycol during the production of polyester. They usually include linear oligomers and cyclic trimers. Linear oligomers account for about 25% of polyester oligomers. Because they have polar end groups in their molecular structure and have a certain solubility in water, they are easy to remove and have little impact. More than 70% of polyester oligomers are cyclic trimers. Because the structure of cyclic trimers is highly symmetrical, they are very easy to aggregate and crystallize. The melting point of the crystals formed is 310°C, and the thermal and chemical stability are high. When the disperse dye is dyed at 130-135°C, the solubility of cyclic trimers is less than 2 mg / L. Therefore, in the polyester dyeing process, cyclic trimers are difficult to be removed. In addition, during the dyeing process of polyester fiber products, with the increase in dyeing temperature and the extension of dyeing time, oligomers will continue to separate from the fibers and migrate to the surface. The oligomers that migrate from the inside of the fiber to the surface will affect the feel and appearance of the polyester fiber, increase the friction of the polyester yarn, and cause the quality of the polyester yarn to decline. Moreover, the oligomers deposited on the surface of polyester fiber products will also cause quality defects such as color difference, color spots and stains.

[0003] In order to avoid the adverse effects of oligomers on polyester fiber products, the traditional method is mainly to use sodium hydrosulfite (Na2S2O4) for reduction cleaning and caustic soda high-temperature soaping after disperse dyeing, but this method has poor oligomer removal effect, and has problems such as long process time, high energy consumption, and large environmental pollution. In the prior art, there are reports on methods of adding oligomer removal aids to prevent oligomer deposition during polyester dyeing. The types of oligomer removers include resin type, anionic type, nonionic type, and cationic type. The resin type oligomer remover has poor alkali resistance and cannot be used in an alkaline bath. At the same time, the resin type oligomer remover will affect the dispersibility of the dye in the acid dyeing bath, and is limited in the dyeing bath processing; in addition, anionic and nonionic oligomer removers are usually used in combination, but the cleaning effect on oligomers is not good, and cationic oligomer removers have the risk of fiber product residue after washing, which will affect the stability of subsequent printing and dyeing processing. That is to say, there is currently no method that can effectively remove oligomers on the surface of polyester fiber products. The art is in urgent need of a technology that can remove oligomers on the surface of polyester fiber products with low cost, high efficiency, environmental protection and simple operation. Summary of the invention

[0004] In view of the above problems and needs in the prior art, the object of the present invention is to provide a method for removing oligomers on the surface of polyester fiber products which is low-cost, efficient, environmentally friendly and easy to operate.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0006] A method for removing oligomers on the surface of polyester fiber products comprises the following steps:

[0007] a) Add polyester fiber products into water, and add 0.1-10g of non-ionic surfactant with HLB value less than 10 per liter of water, wash at 15-60℃ for 5-30 minutes, and then drain;

[0008] b) adding the polyester fiber product washed in step a) into a non-aqueous medium, washing at 15 to 50° C. for 5 to 15 minutes, and then draining the liquid, wherein the non-aqueous medium is at least one selected from tetrachloroethylene, n-butyl acetate, γ-butyrolactone, ε-caprolactone and 1,4-dioxane;

[0009] c) taking out the polyester fiber product cleaned in step b), and placing it in a dryer equipped with a condensation recovery device for sealed drying.

[0010] In a preferred embodiment, in step a), 1 to 5 grams of nonionic surfactant is added to 1 liter of water.

[0011] In a further preferred embodiment, in step a), the HLB value of the nonionic surfactant is 3-7.

[0012] According to a further preferred embodiment, in step a), the nonionic surfactant is selected from any one of Span 65, polyoxyethylene castor oil 10 ether, and isopropyl myristate.

[0013] In a preferred embodiment, in step a), the mass ratio of the polyester fiber product to water is 1:5 to 1:30, preferably 1:10 to 1:20.

[0014] In a preferred embodiment, in step b), the mass ratio of the polyester fiber product to the non-aqueous medium is 1:5 to 1:30, preferably 1:10 to 1:20.

[0015] In a preferred embodiment, in step c), the drying refers to sealing and keeping warm at 50-80° C. for 30-120 minutes.

[0016] In a preferred embodiment, the liquid discharged in step a) is centrifuged to collect water for reuse.

[0017] In a preferred embodiment, the liquid discharged from step b) is subjected to activated carbon adsorption to collect the non-aqueous medium for reuse.

[0018] In addition, it should be noted that the polyester fiber products described in the present invention include polyester yarn, polyester cloth and various polyester fiber products. The method described in the present invention can not only be used for post-cleaning treatment of polyester yarn and polyester cloth after dyeing to replace the reduction cleaning and soaping steps in the existing dyeing process, but also can be used for surface repair treatment of polyester fiber products.

[0019] Compared with the prior art, the present invention has the following significant beneficial effects:

[0020] Experiments have proved that the method of the present invention can not only effectively remove surface oligomers of polyester fiber products, but also is simple to operate and easy to scale up, and the waste liquid can be recycled and reused, with the advantages of low cost, high efficiency and environmental protection. It has important significance and application value in solving quality problems of polyester fiber products such as color stains, floating color, color spots, color difference, etc. caused by surface oligomers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a standard curve used to detect the content of cyclic trimer in a specific embodiment. DETAILED DESCRIPTION

[0022] The technical scheme of the present invention is further described in detail and completely below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0023] The method for determining the surface oligomer content in this application is as follows:

[0024] Drawing of quantitative standard curve: Take PET cyclic trimer (Chinese name: ethylene terephthalate cyclic trimer, cas number 7441-32-9) standard powder (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.), use 1,4-dioxane to prepare 1g / L mother solution, and gradually dilute to 0.02g / L, 0.04g / L, 0.08g / L, 0.10g / L, 0.20g / L, a total of 5 concentrations; inject 5 μL of these standard solutions for high performance liquid chromatography separation, and detect the peak area corresponding to the cyclic trimer; with the concentration of the cyclic trimer as the horizontal axis and the peak area of ​​the liquid chromatography as the vertical axis, establish the relationship curve between the reference peak area and the cyclic trimer concentration (see Figure 1 As shown), using weighted 1 / X 2 The least squares method is used for regression calculation, and the linear regression equation of the relationship between them is obtained as follows: y=4668783.14394x+17669.64962 and its correlation coefficient is: R 2=0.9997;

[0025] Preparation of extract: After cutting the test sample into pieces, weigh 0.5 g and place it in a conical flask, then add 15 mL of 1,4-dioxane and stir at 25°C for 25 minutes to extract oligomers on the surface of polyester fiber products; after the extraction is completed, take 1.5 mL of the extract, filter it with a 0.45 μm organic phase filter head, and use a high performance liquid chromatograph to determine the peak area of ​​the cyclic trimer, and calculate the content of the cyclic trimer (percentage relative to the mass of the test sample);

[0026] HPLC detection and analysis conditions: the stationary phase chromatographic column was a Waters C18 column with an inner diameter of 4.6 mm, a column length of 250 mm, and a filler particle size of 5 μm; mobile phase A was acetonitrile, mobile phase B was deionized water, the mobile phase flow rate was 1.0 mL / min, the column temperature was 40 °C, the detection wavelength was 239 nm, and the injection volume was 5 μL; the elution program was a combination of gradient elution and isocratic elution, 0-15 min, mobile phase A was from 30% volume to 100% volume, and mobile phase B was from 70% volume to 0% volume; isocratic elution was used from 15 to 20 min, and the volume ratio of mobile phase A to mobile phase B was 100%:0%; 20-21 min, mobile phase A was from 100% volume to 30% volume, and mobile phase B was from 0% volume to 70% volume.

[0027] The determination methods of K / S value and L, a, b, ΔE value in this application are as follows:

[0028] Take the test sample, select different positions and use Datacolor 800 colorimeter to measure K / S value and L, a, b, ΔE value, and take the qualified products of the same polyester fiber products as the standard sample; the color difference ΔE indicates the color difference, the smaller the ΔE value, the better, and ΔE <4.3 is considered to be within the acceptable range.

[0029] Example 1

[0030] A method for removing oligomers on the surface of polyester fiber products comprises the following steps:

[0031] a) adding polyester fiber products (in this embodiment, polyester yarns that have been dyed and not subjected to reduction cleaning and soaping treatment in the prior art) into water, with a mass ratio of polyester fiber products to water being 1:10, and adding 1 gram of a nonionic surfactant (in this embodiment, Span 65 is used, but castor oil polyoxyethylene 10 ether or isopropyl myristate may also be used) into 1 liter of water, washing at 60° C. for 10 minutes and then draining the liquid, the discharged liquid may be separated by centrifugation to achieve water recovery and reuse;

[0032] b) adding the polyester fiber product washed in step a) into a non-aqueous medium (perchloroethylene is used in this embodiment, but any one of n-butyl acetate, γ-butyrolactone, ε-caprolactone and 1,4-dioxane may also be used), the mass ratio of the polyester fiber product to the non-aqueous medium being 1:20, washing at 30° C. for 15 minutes and then draining the liquid, and the discharged liquid may be adsorbed by adding activated carbon to achieve the recovery and reuse of the non-aqueous medium;

[0033] c) taking out the polyester fiber product cleaned in step b), putting it into a dryer equipped with a condensation recovery device, and sealing and keeping it warm at 50° C. for 120 minutes to achieve drying of the cleaned polyester fiber product and recovery of the non-aqueous medium.

[0034] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0035] Comparative Example 1

[0036] The main difference between this comparative example and Example 1 is that step b) uses water for washing, and the specific steps are as follows:

[0037] a) adding polyester fiber products (polyester yarns that have been dyed and not subjected to reduction cleaning and soaping treatment in the prior art) into water, with the mass ratio of polyester fiber products to water being 1:10, and adding 1 gram of nonionic surfactant (Span 65) per liter of water, washing at 60°C for 10 minutes and then draining;

[0038] b) adding the polyester fiber product washed in step a) into water, with the mass ratio of the polyester fiber product to water being 1:20, washing at 30° C. for 15 minutes and then draining the liquid;

[0039] c) taking out the polyester fiber product cleaned in step b), putting it into a drying machine, and sealing and keeping it warm at 50° C. for 120 minutes to dry the cleaned polyester fiber product.

[0040] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0041] Example 2

[0042] A method for removing oligomers on the surface of polyester fiber products comprises the following steps:

[0043] a) adding polyester fiber products (in this embodiment, polyester yarns that have been dyed and not subjected to reduction cleaning and soaping treatment in the prior art) into water, with a mass ratio of polyester fiber products to water being 1:15, and adding 2 grams of nonionic surfactant (in this embodiment, isopropyl myristate is used, but Span 65 or castor oil polyoxyethylene 10 ether may also be used) into 1 liter of water, washing at 40° C. for 20 minutes and then draining the liquid, and the discharged liquid may be centrifuged to achieve water recovery and reuse;

[0044] b) adding the polyester fiber product washed in step a) into a non-aqueous medium (in this embodiment, γ-butyrolactone is selected, but any one of tetrachloroethylene, n-butyl acetate, ε-caprolactone and 1,4-dioxane may also be selected), with a mass ratio of the polyester fiber product to the non-aqueous medium being 1:15, washing at 40° C. for 10 minutes and then draining the liquid, and the discharged liquid may be adsorbed by adding activated carbon to achieve recycling of the non-aqueous medium;

[0045] c) taking out the polyester fiber product cleaned in step b), putting it into a dryer equipped with a condensation recovery device, and sealing and keeping it warm at 80° C. for 60 minutes to achieve drying of the cleaned polyester fiber product and recovery of the non-aqueous medium.

[0046] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0047] Comparative Example 2

[0048] The main difference between this comparative example and Example 2 is that step b) uses water for washing, and the specific steps are as follows:

[0049] a) adding polyester fiber products (polyester yarns that have been dyed and not subjected to reduction cleaning and soaping treatment in the prior art) into water, with the mass ratio of polyester fiber products to water being 1:15, and adding 2 grams of nonionic surfactant (isopropyl myristate) per liter of water, washing at 40°C for 20 minutes and then draining;

[0050] b) adding the polyester fiber product washed in step a) into water, with the mass ratio of the polyester fiber product to water being 1:15, washing at 40° C. for 10 minutes and then draining the liquid;

[0051] c) taking out the polyester fiber product cleaned in step b), putting it into a drying machine, and sealing and keeping it warm at 50° C. for 120 minutes to dry the cleaned polyester fiber product.

[0052] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0053] Example 3

[0054] A method for removing oligomers on the surface of polyester fiber products comprises the following steps:

[0055] a) adding polyester fiber products (in this embodiment, polyester yarns that have been dyed and not subjected to reduction cleaning and soaping treatment in the prior art) into water, with a mass ratio of polyester fiber products to water being 1:20, and adding 3 grams of nonionic surfactant (in this embodiment, castor oil polyoxyethylene 10 ether is selected, but Span 65 or isopropyl myristate may also be selected) into 1 liter of water, washing at 50° C. for 15 minutes and then draining the liquid, and the discharged liquid may be centrifuged to achieve water recovery and reuse;

[0056] b) adding the polyester fiber product washed in step a) into a non-aqueous medium (in this embodiment, 1,4-dioxane is selected, but any one of tetrachloroethylene, n-butyl acetate, ε-caprolactone and γ-butyrolactone may also be selected), with a mass ratio of the polyester fiber product to the non-aqueous medium being 1:10, washing at 30° C. for 15 minutes and then draining the liquid, and the discharged liquid may be adsorbed by adding activated carbon to achieve recycling of the non-aqueous medium;

[0057] c) taking out the polyester fiber product cleaned in step b), putting it into a dryer equipped with a condensation recovery device, and sealing and keeping it warm at 60° C. for 80 minutes to achieve drying of the cleaned polyester fiber product and recovery of the non-aqueous medium.

[0058] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0059] Comparative Example 3

[0060] The main difference between this comparative example and Example 3 is that step b) uses water for washing, and the specific steps are as follows:

[0061] a) adding polyester fiber products (polyester yarns that have been dyed and not treated with reduction cleaning and soaping in the prior art) into water, with the mass ratio of polyester fiber products to water being 1:20, and adding 3 grams of nonionic surfactant (castor oil polyoxyethylene 10 ether) per liter of water, washing at 50°C for 15 minutes and then draining;

[0062] b) adding the polyester fiber product washed in step a) into water, with the mass ratio of the polyester fiber product to water being 1:10, washing at 30° C. for 15 minutes and then draining;

[0063] c) taking out the polyester fiber product cleaned in step b), putting it into a drying machine, and sealing and keeping it warm at 50° C. for 120 minutes to dry the cleaned polyester fiber product.

[0064] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0065] Example 4

[0066] A method for removing oligomers on the surface of polyester fiber products comprises the following steps:

[0067] a) adding a polyester fiber product (in this embodiment, a dyed polyester cloth) into water, with a mass ratio of the polyester fiber product to water being 1:15, and adding 2 grams of a nonionic surfactant (in this embodiment, isopropyl myristate is used, but Span 65 or castor oil polyoxyethylene 10 ether may also be used) into 1 liter of water, washing at 50° C. for 15 minutes and then draining the liquid. The discharged liquid may be centrifuged to achieve water recycling;

[0068] b) adding the polyester fiber product washed in step a) into a non-aqueous medium (in this embodiment, ε-caprolactone is selected, but any one of tetrachloroethylene, n-butyl acetate, γ-butyrolactone and 1,4-dioxane may also be selected), with a mass ratio of the polyester fiber product to the non-aqueous medium being 1:20, washing at 30° C. for 15 minutes and then draining the liquid, and the discharged liquid may be adsorbed by adding activated carbon to achieve recycling of the non-aqueous medium;

[0069] c) taking out the polyester fiber product cleaned in step b), putting it into a dryer equipped with a condensation recovery device, and sealing and keeping it warm at 80° C. for 60 minutes to achieve drying of the cleaned polyester fiber product and recovery of the non-aqueous medium.

[0070] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0071] Comparative Example 4

[0072] The main difference between this comparative example and Example 4 is that the dyed polyester cloth is cleaned using the existing technology, and the specific steps are as follows:

[0073] The dyed polyester cloth was added into a cleaning solution containing 5g / L hydrosulfite and 2g / L sodium hydroxide, with the ratio of polyester cloth to water being 1:10. After washing at 60°C for 15 minutes, the liquid was drained and then placed in a dryer, sealed and kept warm at 50°C for 120 minutes to achieve drying of the washed polyester fiber products.

[0074] For the dried polyester fiber products, the surface oligomer content and K / S value and L, a, b, ΔE values ​​were measured according to the above method. The specific measurement results are shown in Table 1 and Table 2, respectively.

[0075] Table 1 Determination results of oligomer content on the surface of polyester fiber products

[0076] Test samples Oligomer content (%) Example 1 0.00894 Comparative Example 1 0.21294 Example 2 0.00761 Comparative Example 2 0.17528 Example 3 0.00547 Comparative Example 3 0.21646 Example 4 0.00735 Comparative Example 4 0.19171

[0077] Table 2 Determination results of K / S value, L, a, b and ΔE value of polyester fiber products

[0078] Test samples K / S value L a b ΔE Example 1 19.526 35.61 50.23 19.61 0.96 Comparative Example 1 19.383 36.81 51.86 20.65 2.22 Example 2 19.841 34.47 49.89 19.87 0.54 Comparative Example 2 19.224 36.41 50.85 19.82 0.98 Example 3 19.485 35.96 50.22 19.98 0.76 Comparative Example 3 19.263 36.51 51.02 18.93 0.96 Example 4 19.632 35.00 50.41 19.66 0.67 Comparative Example 4 18.047 36.93 50.71 18.41 1.49

[0079] It can be seen from the results shown in Table 1 and Table 2 that the method of the present invention can significantly reduce the content of surface oligomers in polyester fiber products, which has significantly progressive and unexpected technical effects compared with the simple use of non-ionic surfactant treatment (such as Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3) and the reduction cleaning of hydrosulfite and alkali soaping treatment in the prior art (such as Example 4 and Comparative Example 4) under the same conditions; and the method of the present invention also has the advantages of simple operation, easy scale-up, waste liquid can be recycled and reused, low cost, high efficiency and environmental protection, and has important significance and application value for solving the quality problems of polyester fiber products such as color stains, floating color, color spots, color difference, etc. caused by surface oligomers.

[0080] In addition, it should be noted that the method of the present invention can also be used for surface repair of polyester fiber products, including clothing and household items.

[0081] Finally, it should be pointed out that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above contents of the present invention all fall within the scope of protection of the present invention.

Claims

1. A method for removing oligomers from the surface of polyester fiber products, characterized in that: The method comprises the following steps: a) Add polyester fiber products into water, and add 0.1-10g of non-ionic surfactant with HLB value less than 10 per liter of water, wash at 15-60℃ for 5-30 minutes, and then drain; b) adding the polyester fiber product washed in step a) into a non-aqueous medium, washing at 15 to 50° C. for 5 to 15 minutes, and then draining the liquid, wherein the non-aqueous medium is at least one selected from tetrachloroethylene, n-butyl acetate, γ-butyrolactone, ε-caprolactone and 1,4-dioxane; c) taking out the polyester fiber product cleaned in step b), and placing it in a dryer equipped with a condensation recovery device for sealed drying.

2. The method according to claim 1, characterized in that: In step a), 1 to 5 grams of a nonionic surfactant is added to 1 liter of water.

3. The method according to claim 1 or 2, characterized in that: In step a), the HLB value of the nonionic surfactant is 3-7.

4. The method according to claim 3, characterized in that: In step a), the nonionic surfactant is selected from any one of Span 65, castor oil polyoxyethylene 10 ether, and isopropyl myristate.

5. The method according to claim 1, characterized in that: In step a), the mass ratio of the polyester fiber product to water is 1:5 to 1:

30.

6. The method according to claim 1, characterized in that: In step b), the mass ratio of the polyester fiber product to the non-aqueous medium is 1:5 to 1:

30.

7. The method according to claim 1, characterized in that: In step c), the drying refers to sealing and keeping warm at 50-80° C. for 30-120 minutes.

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