Low-yellowing polysiloxane as well as preparation method and application thereof

Abstract

The invention discloses low-yellowing polysiloxane which is obtained through reaction of 2, 5, 7-triazabicyclo [2.2. 1] heptane and epoxy-terminated polyether silicone oil in a solvent, the low-yellowing polysiloxane is of a three-dimensional network structure and is large in steric hindrance, a bridge ring is of a rigid structure, a treated fabric is endowed with smooth and elastic performance, the yellowing degree is reduced, and the low-yellowing polysiloxane has the advantages that the anti-yellowing performance is good; the use requirements of clothes are met.

Description

Technical Field

[0001] This application relates to the field of polymer materials, and particularly to a low-yellowing polysiloxane, a preparation method thereof, and an application thereof. Background Art

[0002] Fabric finishing agents play a crucial role in textile processing. They can significantly improve the physical and chemical properties of fabrics, such as imparting softness, wrinkle resistance, hydrophilicity, and abrasion resistance to the fabrics. The improvement of these properties not only enhances the comfort and durability of the fabrics but also meets the needs of consumers for high-quality textiles. In addition, fabric finishing agents can also provide additional functions, such as antibacterial, ultraviolet protection, and flame retardancy, thus expanding the application scope of textiles.

[0003] Silane modification is one of the key technologies for improving the performance of fabric finishing agents. At present, common silane modification methods include amino modification, epoxy modification, and alkoxy modification, etc. These modification technologies can endow polysiloxane with new properties by introducing different functional groups. For example, amino-modified polysiloxane has good softness and hydrophilicity, but it is prone to yellowing due to oxidation. To solve this problem, researchers have tried to use primary amino acylation, etherification modification, or add antioxidants to reduce the yellowing phenomenon. However, while these methods improve the low-yellowing performance, it is often difficult to balance the soft hand feeling of the fabric.

[0004] Yellowing is a common problem in the storage and use of fabrics, especially more obvious in white or light-colored fabrics. Yellowing not only seriously affects the appearance of clothes and reduces their commercial value but also may lead to a decline in fabric performance. For example, the fiber strength at the yellowing part may be weakened, affecting the service life of the clothes. In addition, yellowing may also cause dissatisfaction among consumers, bringing economic losses to enterprises. Therefore, developing a low-yellowing polysiloxane finishing agent is of great significance for improving fabric quality and meeting market demands. Summary of the Invention

[0005] The purpose of this application is to provide a polysiloxane, after treating fabrics with which, the fabrics are not prone to yellowing and can maintain a smooth hand feeling.

[0006] To achieve the above object, the technical solution adopted in this application is: This application provides a low-yellowing polysiloxane, and its structural general formula is where 60 ≤ m ≤ 140, 2 ≤ n ≤ 5, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8.

[0007] The present application also provides a method for preparing a low-yellowing polysiloxane. Add 2,5,7-triazabicyclo[2.2.1]heptane and a solvent into a reaction vessel. After the system is fully dissolved, raise the temperature. Then add an epoxy-terminated polyether silicone oil into the reaction vessel and continue to raise the temperature. Keep the temperature for a period of time to obtain the low-yellowing polysiloxane.

[0008] As a preference, the structural formula of 2,5,7-triazabicyclo[2.2.1]heptane is: The structural formula of the epoxy-terminated polyether silicone oil is: where 60 ≤ m ≤ 140, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8; The structural formula of the low-yellowing polysiloxane is: where 60 ≤ m ≤ 140, 2 ≤ n ≤ 5, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8.

[0009] As another preference, the number-average molecular weight of the epoxy-terminated polyether silicone oil is 6000 - 10000.

[0010] As another preference, the number-average molecular weight of the epoxy-terminated polyether silicone oil is 6000, 7000, 8000, 9000 or 10000.

[0011] As another preference, the equivalent ratio of the epoxy-terminated polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:(1 - 2).

[0012] As another preference, the equivalent ratio of the epoxy-terminated polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.05, 1:1.25, 1:1.5 or 1:1.8.

[0013] Further preferably, the solvent is isopropyl alcohol, and the addition amount of the solvent is 244 - 407 parts by mass.

[0014] Further preferably, specifically, by mass, under the protection of an inert gas, add 10 - 20 parts of 2,5,7-triazabicyclo[2.2.1]heptane and 244 - 407 parts of the solvent into a reaction vessel. After the system is fully dissolved and becomes transparent, start to raise the temperature to about 40°C. Then dropwise add 600 - 1000 parts of the epoxy-terminated polyether silicone oil into the reaction vessel and continue to raise the temperature to 70 - 80°C. Keep the temperature for 6 - 8 h until the system becomes transparent to obtain the low-yellowing polysiloxane.

[0015] The present application also provides a clothing finishing agent, which, by mass, includes 25 parts of an emulsifier, 250 parts of water, 2.5 parts of acetic acid, and 100 parts of the above low-yellowing polysiloxane or the low-yellowing polysiloxane prepared by the above preparation method.

[0016] Compared with the prior art, the beneficial effects of the present application are as follows:

[0017] (1) The low-yellowing polysiloxane of the present application presents a three-dimensional network structure with a large steric hindrance, and oxidation requires crossing a higher activation energy. Therefore, the yellowing degree of the fabric treated with it as a clothing finishing agent is smaller.

[0018] (2) The bridge ring in the low-yellowing polysiloxane of the present application is a rigid structure, and the atomic activity is restricted. While the siloxane is a non-rigid active chain segment, combining rigidity and flexibility to form a three-dimensional network structure in space, enhancing the atomic space utilization rate. After ring-opening, the naked hydroxyl groups can form three-dimensional network hydrogen bonds with the fabric, endowing the treated fabric with a smooth and elastic property, meeting the usage requirements of clothing.

[0019] (3) The present application uses 2,5,7-triazabicyclo[2.2.1]heptane to react with bis-terminal epoxy polyether silicone oil, and through ring-opening polymerization, a bridge-ring modified tertiary amine type polysiloxane is formed. The preparation method has simple operation, mild conditions, and easily available raw materials, and the generated product has a stable structure and properties, and is suitable for use as a fabric finishing agent. Specific Embodiments

[0020] Next, in combination with specific embodiments, the present application will be further described. It should be noted that, on the premise of no conflict, any combination of the following-described embodiments or technical features can form a new embodiment.

[0021] The terms "comprising" and "having" in the specification and claims of the present application and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0022] The present application provides a low-yellowing polysiloxane, and its structural general formula is: Where 60 ≤ m ≤ 140, 2 ≤ n ≤ 5, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8.

[0023] The low-yellowing polysiloxane of the present application presents a three-dimensional network structure with a large steric hindrance, and oxidation requires crossing a higher activation energy. Therefore, the yellowing degree of the fabric treated with it as a clothing finishing agent is smaller.

[0024] In the low-yellowing polysiloxane of the present application, the bridged ring is a rigid structure with restricted atomic activity, while the siloxane is a non-rigid active chain segment. The combination of rigidity and flexibility forms a three-dimensional network structure in space, enhancing the atomic space utilization rate. After ring-opening, the naked hydroxyl groups can form three-dimensional network hydrogen bonds with the fabric, endowing the treated fabric with smooth and elastic properties and meeting the usage requirements of clothing.

[0025] The present application provides a preparation method of a low-yellowing polysiloxane: Add 2,5,7-triazabicyclo[2.2.1]heptane and a solvent into a reaction vessel. After the system is fully dissolved, raise the temperature. Then add terminal epoxy polyether silicone oil into the reaction vessel and continue to raise the temperature. Keep the temperature for a certain period of time to obtain a low-yellowing polysiloxane of the present application.

[0026] Among them, 2,5,7-triazabicyclo[2.2.1]heptane is a solid with a purity of 98%, a molecular weight of 99.14, CAS: 279-43-6, and the structural formula is:

[0027] The solid content of the low-yellowing polysiloxane is about 70%, and its structural formula is: Among them, 60 ≤ m ≤ 140, 2 ≤ n ≤ 5, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8.

[0028] In some preferred embodiments, the terminal epoxy polyether silicone oil is a bis-terminal epoxy polyether silicone oil with a solid content of 98%, and its structural formula is: Among them, 60 ≤ m ≤ 140, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8.

[0029] The synthesis route of the low-yellowing polysiloxane of the present application is: Among them, 60 ≤ m ≤ 140, 3 ≤ x ≤ 10, 2 ≤ y ≤ 8.

[0030] The present application uses 2,5,7-triazabicyclo[2.2.1]heptane to react with bis-terminal epoxy polyether silicone oil to form a bridged-ring modified tertiary amine type polysiloxane through ring-opening polymerization. The preparation method is simple in operation, mild in conditions, and easy to obtain raw materials. The generated product has a stable structure and properties and is suitable for use as a fabric finishing agent.

[0031] In some embodiments, the number-average molecular weight of the terminal epoxy polyether silicone oil is 6000 - 10000. In more preferred embodiments, the number-average molecular weight of the terminal epoxy polyether silicone oil is 6000, 7000, 8000, 9000, or 10000.

[0032] In some embodiments, the equivalent ratio of the terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:(1 - 2).

[0033] In some more preferred embodiments, the equivalent ratio of the terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.05, 1:1.25, 1:1.5, or 1:1.8.

[0034] In some embodiments, the solvent is isopropanol, and the addition amount of isopropanol is 244 to 407 parts by mass.

[0035] In the infrared spectrum data, the single peak at 3336 cm -1 is for -OH; the stretching vibration absorption peak of the tertiary amine C-N bond appears at 1260 cm -1 ; the absorption peak of the Si-O-Si bond appears at 1018 - 1091 cm -1 All of the above prove the formation of the low-yellowing polysiloxane.

[0036] Specifically, the preparation method of the low-yellowing polysiloxane is as follows: Under the protection of an inert gas, 2,5,7-triazabicyclo[2.2.1]heptane and the solvent are added to a reaction vessel. After the system is fully dissolved and becomes transparent, the temperature is raised to about 40°C. Then, the terminal epoxy polyether silicone oil is added dropwise to the reaction vessel, and the temperature is further raised to 70 - 80°C. The reaction is carried out under insulation for 6 - 8 h until the system becomes transparent, obtaining a low-yellowing polysiloxane of the present application.

[0037] The present application also provides a fabric finishing agent, which includes, by mass, 100 parts of the above-mentioned low-yellowing polysiloxane, 25 parts of an emulsifier, 250 parts of water, and 2.5 parts of acetic acid.

[0038] Example 1

[0039] Under a nitrogen atmosphere, 10.4 parts by mass of 2,5,7-triazabicyclo[2.2.1]heptane is added to a reaction kettle, and then 244 parts by mass of isopropanol is added. After complete dissolution, the system becomes transparent. The temperature is raised to about 40°C, and 600 parts by mass of the terminal epoxy polyether silicone oil with a number-average molecular weight of 6000 is added dropwise to the reaction kettle at a rate of 300 ml / h. The equivalent ratio of the terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.05. After the addition is completed, the temperature is further raised to about 75 - 80°C, and the reaction is carried out under insulation for 8 hours until the system becomes transparent, and then the reaction is stopped, obtaining a low-yellowing polysiloxane.

[0040] Example 2

[0041] The number-average molecular weight of the terminal epoxy polyether silicone oil is adjusted to 7000, and the addition amount is adjusted to 700 parts by mass. The addition amount of isopropanol is correspondingly adjusted to 284 parts by mass. Other preparation methods are the same as those in Example 1.

[0042] Example 3

[0043] Adjust the number-average molecular weight of the terminal epoxy polyether silicone oil to 8000, adjust the addition amount to 800 parts by mass, and correspondingly adjust the addition amount of isopropanol to 324 parts by mass. Keep the other preparation methods consistent with the preparation steps in Example 1.

[0044] Example 4

[0045] Adjust the number-average molecular weight of the terminal epoxy polyether silicone oil to 9000, adjust the addition amount to 900 parts by mass, and correspondingly adjust the addition amount of isopropanol to 364 parts by mass. Keep the other preparation methods consistent with the preparation steps in Example 1.

[0046] Example 5

[0047] Adjust the number-average molecular weight of the terminal epoxy polyether silicone oil to 10000, adjust the addition amount to 1000 parts by mass, and correspondingly adjust the addition amount of isopropanol to 404 parts by mass. Keep the other preparation methods consistent with the preparation steps in Example 1.

[0048] Example 6

[0049] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 12.4 parts by mass. The equivalent ratio of the terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.25. Correspondingly, adjust the addition amount of isopropanol to 245 parts by mass. Keep the other preparation steps consistent with the preparation steps in Example 1.

[0050] Example 7

[0051] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 14.9 parts by mass. The equivalent ratio of the terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.5. Correspondingly, adjust the addition amount of isopropanol to 246 parts by mass. Keep the other preparation steps consistent with the preparation steps in Example 1.

[0052] Example 8

[0053] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 17.8 parts by mass. The equivalent ratio of the terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.8. Correspondingly, adjust the addition amount of isopropanol to 247 parts by mass. Keep the other preparation steps consistent with the preparation steps in Example 1.

[0054] Example 9

[0055] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 12.4 parts by mass, the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.25, correspondingly adjust the addition amount of isopropanol to 285 parts by mass, adjust the number-average molecular weight of terminal epoxy polyether silicone oil to 7000, and adjust the addition amount to 700 parts by mass. Other preparation steps are the same as those in Example 1.

[0056] Example 10

[0057] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 14.9 parts by mass, the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.5, correspondingly adjust the addition amount of isopropanol to 286 parts by mass. Other preparation steps are the same as those in Example 9.

[0058] Example 11

[0059] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 17.8 parts by mass, the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.8, correspondingly adjust the addition amount of isopropanol to 287 parts by mass. Other preparation steps are the same as those in Example 9.

[0060] Example 12

[0061] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 12.4 parts by mass, the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.25, correspondingly adjust the addition amount of isopropanol to 325 parts by mass, adjust the number-average molecular weight of terminal epoxy polyether silicone oil to 8000, and adjust the addition amount to 800 parts by mass. Other preparation steps are the same as those in Example 1.

[0062] Example 13

[0063] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 14.9 parts by mass, the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.5, correspondingly adjust the addition amount of isopropanol to 326 parts by mass. Other preparation steps are the same as those in Example 12.

[0064] Example 14

[0065] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 17.8 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.8. Accordingly, adjust the addition amount of isopropanol to 327 parts by mass, and keep other preparation steps the same as those in Example 12.

[0066] Example 15

[0067] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 12.4 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.25. Accordingly, adjust the addition amount of isopropanol to 365 parts by mass, adjust the number-average molecular weight of terminal epoxy polyether silicone oil to 9000, and adjust the addition amount to 900 parts by mass. Keep other preparation steps the same as those in Example 1.

[0068] Example 16

[0069] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 14.9 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.5. Accordingly, adjust the addition amount of isopropanol to 366 parts by mass, and keep other preparation steps the same as those in Example 15.

[0070] Example 17

[0071] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 17.8 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.8. Accordingly, adjust the addition amount of isopropanol to 367 parts by mass, and keep other preparation steps the same as those in Example 15.

[0072] Example 18

[0073] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 12.4 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.25. Accordingly, adjust the addition amount of isopropanol to 405 parts by mass, adjust the number-average molecular weight of terminal epoxy polyether silicone oil to 10000, and adjust the addition amount to 1000 parts by mass. Keep other preparation steps the same as those in Example 1.

[0074] Example 19

[0075] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 14.9 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.5. Accordingly, adjust the addition amount of isopropanol to 406 parts by mass, and keep the other preparation steps the same as those in Example 18.

[0076] Example 20

[0077] Adjust the addition amount of 2,5,7-triazabicyclo[2.2.1]heptane to 17.8 parts by mass, and the equivalent ratio of terminal epoxy polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.8. Accordingly, adjust the addition amount of isopropanol to 407 parts by mass, and keep the other preparation steps the same as those in Example 18.

[0078] Comparative Example 1

[0079] Polyether diamine D230 modified polysiloxane sample.

[0080] Comparative Example 2

[0081] Polyether diamine ED900 modified polysiloxane sample.

[0082] Comparative Example 3

[0083] Polyether triamine T403 modified polysiloxane sample.

[0084] Prepare polysiloxane emulsion: Mix 100 parts by mass of the polysiloxane prepared in each example and each comparative example with 25 parts by mass of emulsifier 1350 / 1370, 250 parts by mass of water and 2.5 parts by mass of acetic acid, and mechanically emulsify to obtain a transparent and slightly blue-light-emitting emulsion, thus obtaining a 25% polysiloxane emulsion.

[0085] Color change test finishing process: Pad the white cotton knitted fabric with the working fluid, where the working fluid is 30 g / L of polysiloxane emulsion, the padding rate is 70%, enter the pre-baking stage, set the temperature of the pre-baking stage to 180°C, the baking time to 15 - 45 s, and finally carry out aftertreatment for 1 hour, and then evaluate the color change of the prepared samples.

[0086] Handfeel evaluation finishing process: Pad the navy blue nylon-cotton fabric with the working fluid, where the working fluid is 8 g / L of polysiloxane emulsion, the padding rate is 70%, enter the pre-baking stage, set the temperature of the pre-baking stage to 140°C, the baking time to 15 - 45 s, and finally carry out aftertreatment for 1 hour, and then evaluate the handfeel of the prepared samples.

[0087] Performance evaluation test

[0088] 1. Color change evaluation test: Use X-Rite spectrophotometer (model: Ci7800) for measurement, illuminated by pulsed xenon arc light source, diffuse illumination and 8° observation angle (d / 8), and the measurement area is 25mm (1 inch). After calibrating the instrument in black and white, the measurement is carried out on the control sample with standard white tile as the backing and the sample to be tested with standard white tile as the backing, with the front side of the fabric as the test surface, to obtain the measurement values ​​of L, a and b, which describe the coordinate space of light / dark, red / green and blue / yellow. △L* is the lightness difference, the larger the value, the greater the depth difference from the original fabric. △a* is the red-green light difference, the more positive, the more reddish. △b* is the yellow-blue light difference, the more positive, the more yellowish. △E* is the total color difference, the larger the value, the greater the total color difference from the original fabric.

[0089] 2. Anti-yellowing performance evaluation test: DATACOLOR 200M LAV / (D65 / 10°) was used, and the sample was 24 pieces of 30mm*30mm warp and weft knitted white cotton knitted fabrics. Each piece of the sample was tested 4 times and the average value was taken. The color change evaluation test results and the yellowing performance test results of each embodiment and each comparative example are recorded in Table 1.

[0090] 3. Hand feel evaluation test: The hand feel was evaluated by touching the sample with hands, and the overall hand feel was evaluated with a score of 1 to 5, with 1 being the worst and 5 being the best. Ten people evaluated the sample at the same time, and the average value was taken. The hand feel evaluation test results of each embodiment and each comparative example are recorded in Table 2.

[0091] 4. Fabric elastic performance evaluation test: This experiment refers to FZ / T01034-2008 "Textile Woven Fabric Tensile Elasticity Test Method", and uses YG025H-250 electronic fabric strength machine to test the tensile properties of fabrics. Sample: 24 pieces of 200mm*50mm warp and weft knitted dark blue brocade spandex fabric, with a spacing of 100mm, each sample is measured 4 times, and the average value is taken; in standard atmosphere, that is, humidity (20±2)℃. Balance for 24 hours under relative humidity (65±2)%, the initial tension is set to 0.2N, the stretching speed is 50mm / min, and the stretching is repeated 3 times, the average value is taken, and the stretching residence time is 60s. The maximum elongation of human skin is about 40% in the horizontal direction and about 80% in the vertical direction. When the fixed elongation is 60%, the tensile force in the transverse and longitudinal directions is measured, and the unidirectional fixed elongation elastic recovery rate and fixed elongation plastic deformation rate are calculated. The elasticity test results of each embodiment and each comparative example are recorded in Table 3.

[0092] Table 1 Color change and yellowing test results of polysiloxane emulsion applied to white cotton fabric

[0093] Analyze the color change and yellowness data in Table 1. The highest whiteness is 145.19, and the lowest yellowing is -27.69. This condition is almost close to the test results of the blank sample and higher than the test results of each comparative example. The whiteness values of the low-yellowing polysiloxane emulsions prepared in each example of the present application are close to 140, and the absolute value of the yellowing data is greater than 24. Therefore, the low-yellowing polysiloxane of the present application can be used as a fabric softener to reduce the yellowing of cotton fabrics, improve the whiteness, and make the clothes more durable.

[0094] Table 2 Handfeel evaluation results of the emulsions of each example and each comparative example applied to navy blue nylon-ammonia

[0095] From the handfeel evaluation test results in Table 2, it can be seen that the polysiloxane emulsion prepared in Comparative Example 1 has good softness and smoothness in handfeel and good elasticity, and the comprehensive evaluation is 4 points; the polysiloxane emulsion prepared in Comparative Example 2 has good softness in handfeel, and good smoothness and elasticity, and the comprehensive evaluation is 3 - 4 points; the polysiloxane emulsion prepared in Comparative Example 3 shows poor softness, but good smoothness and elasticity, and the comprehensive score is 3 points. The handfeel evaluation of the low-yellowing polysiloxane emulsion prepared in the present application applied to navy blue nylon-ammonia is basically 3 - 4 points. The handfeel after the treatment of the low-yellowing polysiloxane in Examples 8, 12, and 13 takes into account softness, smoothness, and elasticity, and the comprehensive evaluation reaches 4 points.

[0096] Table 3 Elasticity evaluation test of each example and each comparative example

[0097] Analyze the elasticity evaluation test results in Table 3. It can be seen that the unit tensile elastic properties in the longitudinal direction are better than those in the transverse direction. For the fabrics treated with the low-yellowing polysiloxane in each example of the present application, their unidirectional tensile elastic recovery rate is higher and the plastic deformation rate is lower. The greater the elastic recovery rate and the smaller the plastic deformation rate, the better the elasticity. The low-yellowing polysiloxane of the present application acts on navy blue nylon-ammonia fabrics, achieving the effect of reducing yellowing while improving the elasticity of the fabrics, making the fabrics more comfortable to wear.

[0098] Based on the above performance evaluation test results, for the polysiloxane emulsion of Comparative Example 1, although the hand feeling is softened, it is prone to yellowing. After the fabrics are treated with the polysiloxane emulsions prepared in Comparative Example 2 and Comparative Example 3, they have good slippery and elastic properties and low yellowing, but the soft and slippery degree of the hand feeling decreases significantly. After the low-yellowing polysiloxane prepared in this application is applied to fabric finishing, it maintains the whiteness of the clothing and takes into account softness, smoothness and elasticity. The comprehensive evaluation of the hand feeling is 4 points. For the horizontal tensile elastic recovery rate of navy blue nylon spandex, it reaches 97.48%, the plastic deformation rate is 2.52%, the longitudinal tensile elastic recovery rate is 98.56%, and the plastic deformation rate is 1.44%. The elasticity is very good and is consistent with the evaluation result by the hand-touch method.

[0099] The above describes the basic principle, main features and advantages of this application. Those skilled in the art should understand that this application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of this application. Without departing from the spirit and scope of this application, this application will have various changes and improvements, and these changes and improvements all fall within the scope of this application claimed. The scope of protection required by this application is defined by the appended claims and their equivalents.

Claims

1. A low-yellowing polysiloxane, characterized in that: Its general structural formula is: Among them, 60≤m≤140, 2≤n≤5, 3≤x≤10, 2≤y≤8.

2. A method for preparing a low-yellowing polysiloxane, characterized in that: 2,5,7-triazabicyclo[2.2.1]heptane and a solvent are added to a reaction container, and the temperature is raised after the system is fully dissolved. After epoxy-terminated polyether silicone oil is added to the reaction container, the temperature is continued to be raised, and the reaction is kept at the temperature for a period of time to obtain the low-yellowing polysiloxane.

3. The preparation method according to claim 2, characterized in that: The structural formula of the 2,5,7-triazabicyclo[2.2.1]heptane is: The structural formula of the epoxy-terminated polyether silicone oil is: Among them, 60≤m≤140, 3≤x≤10, 2≤y≤8; The structural formula of the low-yellowing polysiloxane is: Among them, 60≤m≤140, 2≤n≤5, 3≤x≤10, 2≤y≤8.

4. The preparation method according to claim 2, characterized in that: The number average molecular weight of the epoxy-terminated polyether silicone oil is 6,000 to 10,000.

5. The preparation method according to claim 4, characterized in that: The number average molecular weight of the epoxy-terminated polyether silicone oil is 6000, 7000, 8000, 9000 or 10000.

6. The preparation method according to claim 2, characterized in that: The equivalent ratio of the epoxy-terminated polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:(1-2).

7. The preparation method according to claim 6, characterized in that: The equivalent ratio of the epoxy-terminated polyether silicone oil to 2,5,7-triazabicyclo[2.2.1]heptane is 1:1.05, 1:1.25, 1:1.5 or 1:1.

8.

8. The preparation method according to claim 2, characterized in that: The solvent is isopropanol, and the added amount of the solvent is 244 to 407 parts by weight.

9. The preparation method according to claim 2, characterized in that: Specifically, by mass, under the protection of inert gas, 10 to 20 parts of the 2,5,7-triazabicyclo[2.2.1]heptane and 244 to 407 parts of the solvent are added to a reaction container, and the temperature is raised to about 40° C. after the system is fully dissolved and becomes transparent, 600 to 1000 parts of the epoxy-terminated polyether silicone oil are added dropwise to the reaction container, and the temperature is continued to rise to 70 to 80° C. The reaction is kept warm for 6 to 8 hours until the system becomes transparent, thereby obtaining the low-yellowing polysiloxane.

10. A clothing finishing agent, characterized in that: The composition comprises, by weight, 25 parts of an emulsifier, 250 parts of water, 2.5 parts of acetic acid, and 100 parts of the low-yellowing polysiloxane according to claim 1, or the low-yellowing polysiloxane prepared by the preparation method according to claims 2 to 9.

Images