A silicone emulsion defoamer for textiles and its preparation method

Abstract

This invention discloses a silicone emulsion defoamer for textiles and its preparation method. It is prepared from the following components by weight percentage: 5%-40% polysiloxane silicone paste, 0.3%-20% silicone polyether, 1%-20% emulsifier, 0.1%-5% thickener, 0.05%-0.3% bactericide, and the balance being water, with the sum of the weight percentages of all components being 100%. The stability of the emulsion under high temperature and high pressure environments is improved by using cross-linked polysiloxane silicone paste and silicone polyether with a specific structure. The cross-linked polysiloxane silicone paste provides superior defoaming and foam-suppressing performance. Utilizing the intertwined spatial structure of the high-viscosity silicone composition and the silicone polyether, the defoamer prepared by this method not only exhibits good stability under high temperature and alkaline environments but also significantly improves its late-stage foam-suppressing performance in sizing. More importantly, it enhances the compatibility between the silicone emulsion defoamer and the sizing.

Description

Technical Field

[0001] This invention belongs to the technical field of silicone defoamers, specifically relating to a silicone emulsion defoamer for textiles and its preparation method. Background Technology

[0002] Organosilicon emulsion defoamers are among the most important organosilicon defoamer products. Due to their unique properties and characteristics, they are widely used in industry, including papermaking, textiles, pulp and paper, coatings, construction, leather, pharmaceuticals, and cosmetics. Their application areas are constantly expanding, demonstrating significant potential. Among these applications, using organosilicon in the form of an aqueous emulsion is the most economical, convenient, and safe, while also meeting environmental protection requirements.

[0003] In textile dyeing and finishing processes, especially in steps such as sizing, synthetic fiber oiling, scouring, dyeing, and finishing, large quantities of surfactants such as penetrants, leveling agents, dispersants, and fixing agents are used. These surfactants, combined with raw materials such as detergents and adhesives, form foaming liquids. Air is introduced during stirring, transmission, and liquid conveying, generating a large amount of foam, which in turn causes various malfunctions, negatively impacting dyeing quality and severely affecting product quality. Therefore, defoamers are needed to effectively eliminate foam that causes production problems and affects product quality.

[0004] Currently used defoamers are mostly water-based liquid formulations, primarily classified into three categories: silicone-based, polyether-based, and mineral oil-based. Silicone-based defoamers are silicone pastes synthesized with polysiloxane as the main component, combined with emulsifiers, thickeners, dispersants, bactericides, etc., and obtained through mechanical emulsification with water. Polyether-based and mineral oil-based defoamers are not widely used in the textile industry due to their large usage and low defoaming efficiency.

[0005] Organosilicon defoamers are currently the most widely used type of defoamer due to their low surface tension, good chemical stability, and excellent defoaming and foam-suppressing properties, making them the most widely used in the textile printing and dyeing industry. High-temperature organosilicon defoamers are used for dyeing synthetic fibers, especially polyester. Because of the high dyeing temperatures (130–140℃) and pressures (2–4 atmospheres), ordinary defoamers will demulsify or become oily at these temperatures, causing silicone oil stains on the dyed synthetic fiber fabrics, resulting in defective or waste products. Furthermore, due to the ineffectiveness of the defoamer, foam cannot be effectively eliminated during dyeing, preventing the dye liquor from making good contact with the fabric, leading to color differences, color spots, and other defects. Therefore, defoamers are an indispensable auxiliary agent in the high-temperature dyeing process of synthetic fibers (especially polyester and polyester-cotton blends). During the dyeing process, especially when dyeing polyester, the high temperature (130-140℃), high pressure (2-4 atmospheres), and strong alkalinity (pH 11-14) cause ordinary silicone defoamers to demulsify under these high temperature and high pressure conditions, resulting in silicone oil adhering to the dyed fabric and forming silicone spots. Summary of the Invention

[0006] This invention addresses the aforementioned problems by innovatively providing a silicone emulsion defoamer for textiles and its preparation method. By using a silicone polyether with a spatial structure to emulsify a high-viscosity silicone composition, and based on the principle of "like dissolves like," the defoamer is prepared by intertwining the spatial structures of the high-viscosity silicone composition and the silicone polyether. This method not only ensures good stability under high temperature and alkaline conditions but also significantly improves its late-stage foam suppression performance in slurries. More importantly, it enhances the compatibility between the silicone emulsion defoamer and the slurry. In terms of the preparation process, this silicone defoamer has a simple reaction flow, mild process conditions, low operating requirements, and is easier to produce.

[0007] To achieve the above objectives, the specific solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a silicone emulsion defoamer for textiles, which is prepared by weight percentage from the following components: 5%-40% polysiloxane silicone paste, 0.3%-20% silicone polyether, 1%-20% emulsifier, 0.1%-5% thickener, 0.05%-0.3% bactericide, and the balance being water, wherein the sum of the weight percentages of each component is 100%.

[0009] Preferably, the preferred contents of each component in the textile silicone emulsion defoamer are as follows: by weight percentage, it is prepared from the following components: 10%-35% polysiloxane silicone paste, 1%-15% silicone polyether, 2%-13% emulsifier, 0.1%-5% thickener, 0.05%-0.3% bactericide, and the balance is water, and the sum of the weight percentages of each component is 100%.

[0010] Furthermore, the preferred forms of each component in the above formulation are as follows:

[0011] (1) Polysiloxane silicone paste

[0012] It is a high-viscosity organosilicon composition, which is made of polyorganosiloxane, fumed silica, silicone resin and catalyst through a certain process. Its dynamic viscosity at 25°C is 400,000 to 800,000 mPa·s.

[0013] Among them, the polyorganosiloxane is selected from polyvinylsiloxane (PEOS) or polymethylsiloxane (PMOS);

[0014] Silica is selected from precipitated silica. Both traditional precipitated silica and special precipitated silica are acceptable. The former refers to silica produced using sulfuric acid, hydrochloric acid, CO2 and water glass as basic raw materials, while the latter refers to silica produced using special methods such as high gravity technology, sol-gel method, chemical crystal method, secondary crystallization method or reverse micelle microemulsion method.

[0015] Both the silicone resin and the catalyst are commercially available.

[0016] Polysiloxane silicone paste is prepared according to existing methods, such as the method in US4639489 patent.

[0017] (2) The structural formula of silicone polyether is as follows:

[0018]

[0019] Where R is a hydrogen atom, methyl, ethyl, propyl or butyl; subscript x is an integer from 1 to 50, y is an integer from 30 to 500, z is an integer from 1 to 50, p is an integer from 50 to 500; subscripts n and m are both integers from 1 to 50, and q is an integer from 1 to 8.

[0020] This silicone polyether has good dispersibility and more stable performance, which helps to improve the emulsification of silicone paste and also improves the defoaming performance of defoamers.

[0021] (3) The emulsifier is a nonionic surfactant, an anionic surfactant, or a combination of both.

[0022] Nonionic surfactants are selected from fatty acid polyoxyethylene ethers, including lauric acid polyoxyethylene ether, oleic acid polyoxyethylene ether, palmitic acid polyoxyethylene ether, stearic acid polyoxyethylene ether; fatty alcohol polyoxyethylene ethers, including stearic acid polyether, glycerol polyether, etc.; glycerol esters, including glycerol stearate, glycerol oleate; sorbitol derivatives, including sorbitan monostearate (Span-60), sorbitan monooleate (Span-80), sorbitan tristearate (Span-65), sorbitan trioleate (Span-85), polyoxyethylene sorbitan ether stearate (Tween-60), sorbitan monooleate polyoxyethylene ether (Tween-80), polyoxyethylene sorbitan tristearate (Tween-65), polyoxyethylene sorbitan trioleate (Tween-85); castor oil polyoxyethylene ether, etc.

[0023] Anionic surfactants are selected from sulfate salts, including sodium lauryl polyoxyethylene ether sulfate, 3-acylglycerol-1,2-disulfate salt, and sodium dodecyl sulfate; and sulfonates, including sodium potassium lauryl sulfonate, sodium ethylhexanol succinate sulfonate, sodium N,N-oleoylmethyl taurate, sodium butylnaphthalene sulfonate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate, sodium hexadecylbenzene sulfonate, and sodium dodecyl diphenyl ether disulfonate, etc.

[0024] In a preferred embodiment, the emulsifier can be obtained commercially. The nonionic surfactant is selected from different types of fatty alcohol polyoxyethylene ethers Brij72, Brij721, BrijL23, Brij58 and sorbitol derivatives Span 60, Tween 60, Tween 80; the anionic surfactant is commercially available sodium dodecyl sulfate and sodium dodecylbenzene sulfonate. The nonionic and anionic surfactants can be used alone or in combination.

[0025] (4) The thickener can be a cellulose-based thickener or a polyacrylate-based thickener, preferably any one of the polyacrylate-based thickeners. Polyacrylate-based thickeners have good alkali resistance, which can ensure that the defoamer is stable under highly alkaline conditions in textile applications.

[0026] (5) Any bactericide can be selected and obtained through commercial channels.

[0027] A second aspect of the present invention provides a method for preparing the above-mentioned silicone emulsion defoamer for textiles, comprising the following steps:

[0028] (1) Add the formulated amount of polysiloxane silicone paste, silicone polyether, emulsifier and thickener to the emulsification kettle, stir at 55℃-65℃ for 1-3 hours, mix evenly, and the stirring speed is 100-800 rpm.

[0029] (2) Cool down to 20℃-40℃, slowly add water, and emulsify at high speed of 800rpm-2000rpm;

[0030] (3) Reduce the speed, add bactericide, and continue stirring at 100rpm-300rpm for 10-20 minutes to obtain the defoamer emulsion.

[0031] The technical effects of this invention are as follows:

[0032] In terms of effectiveness, the defoamer provided by this invention improves the stability of emulsions under high temperature and high pressure environments through cross-linked polysiloxane silicone paste and silicone polyether with a specific structure. The cross-linked polysiloxane silicone paste provides superior defoaming and foam-suppressing performance. Utilizing the intertwined spatial structures of the high-viscosity organosilicon composition and the silicone polyether, the defoamer prepared by this method not only exhibits good stability under high temperature and alkaline conditions but also significantly improves its late-stage foam-suppressing performance in slurries. More importantly, it enhances the compatibility between the organosilicon emulsion defoamer and the slurry. Experimental results show that the defoamer of this invention, after being kept at 130℃ and 2 atmospheres for 30 minutes, shows almost no precipitation after cooling, making it more suitable for application in the textile printing and dyeing industry.

[0033] In terms of preparation process, the method for preparing the high-temperature and high-pressure resistant defoamer provided by this invention has simple steps, mild reaction conditions, low requirements for process and equipment, high production efficiency, and is conducive to industrial-scale production. Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0035] The polysiloxane silicone paste and silicone polyether used in the examples and comparative examples are selected from those shown in Table 1 below:

[0036] Table 1 Summary of Polysiloxane Silicone Paste and Silicone Polyether in the Comparative Examples

[0037]

[0038] Example 1

[0039] A high-temperature and high-pressure resistant defoamer for textile applications is prepared according to the following steps: 40% polysiloxane silicone paste, 20% silicone polyether, 5% lauric acid polyoxyethylene ether, and 2% thickener are added to an emulsifying tank and stirred at 55°C for 3 hours at a stirring speed of 100 rpm; the temperature is lowered to 20°C, and the remaining water is slowly added, followed by high-speed mechanical emulsification at 800 rpm; the stirring speed is reduced to 100 rpm, 0.15% bactericide is added, and stirring is continued for 10 minutes to obtain the defoamer emulsion.

[0040] Example 2

[0041] A high-temperature and high-pressure resistant defoamer for textile applications is prepared according to the following steps: 30% polysiloxane silicone paste, 13% silicone polyether, 10% lauric acid polyoxyethylene ether, and 3% thickener are added to an emulsifying tank and stirred at 60°C for 3 hours at a stirring speed of 300 rpm; the temperature is lowered to 20°C, and the remaining water is slowly added, followed by high-speed mechanical emulsification at 1000 rpm; the stirring speed is reduced to 100 rpm, 0.15% bactericide is added, and stirring is continued for 10 minutes to obtain the defoamer emulsion.

[0042] Example 3

[0043] A high-temperature and high-pressure resistant defoamer for textile applications is prepared according to the following steps: 20% polysiloxane silicone paste, 7% silicone polyether, 10% lauric acid polyoxyethylene ether, and 3% thickener are added to an emulsifying kettle and stirred at 60°C for 3 hours at a stirring speed of 500 rpm; the temperature is lowered to 20°C, and the remaining water is slowly added, followed by high-speed mechanical emulsification at 1000 rpm; the stirring speed is reduced to 100 rpm, 0.15% bactericide is added, and stirring is continued for 10 minutes to obtain the defoamer emulsion.

[0044] Example 4

[0045] A high-temperature and high-pressure resistant defoamer for textile applications is prepared according to the following steps: 20% polysiloxane silicone paste, 10% silicone polyether, 15% lauric acid polyoxyethylene ether, and 3% thickener are added to an emulsifying kettle and stirred at 60°C for 3 hours at a stirring speed of 500 rpm; the temperature is lowered to 20°C, and the remaining water is slowly added, followed by high-speed mechanical emulsification at 1000 rpm; the speed is reduced to 100 rpm, 0.15% bactericide is added, and stirring is continued for 10 minutes to obtain the defoamer emulsion.

[0046] Comparative Example 1

[0047] A high-temperature and high-pressure resistant defoamer for textile applications is prepared according to the following steps: 20% polysiloxane silicone paste, 7% silicone polyether, 10% lauric acid polyoxyethylene ether, and 3% thickener are added to an emulsifying kettle and stirred at 60°C for 3 hours at a stirring speed of 500 rpm; the temperature is lowered to 20°C, and the remaining water is slowly added, followed by high-speed mechanical emulsification at 1000 rpm; the stirring speed is reduced to 100 rpm, 0.15% bactericide is added, and stirring is continued for 10 minutes to obtain the defoamer emulsion.

[0048] Comparative Example 1

[0049] A high-temperature and high-pressure resistant defoamer for textile applications is prepared according to the following steps: 20% polysiloxane silicone paste, 15% lauric acid polyoxyethylene ether, and 3% thickener are added to an emulsifying kettle and stirred at 60°C for 3 hours at a stirring speed of 500 rpm; the temperature is lowered to 20°C, and the remaining water is slowly added, followed by high-speed mechanical emulsification at 1000 rpm; the stirring speed is reduced to 100 rpm, and 0.15% bactericide is added, and stirring is continued for 10 minutes to obtain the defoamer emulsion.

[0050] Effect Comparison

[0051] The following performance tests were performed on the above embodiments and comparative examples:

[0052] 1. High temperature and high pressure stability test

[0053] The testing method is as follows:

[0054] (1) Dilute the prepared defoamer to a solid content of 5% for later use;

[0055] (2) Take a 250ml beaker, add 5g of diluted defoamer and 195g of tap water;

[0056] (3) Place the beaker containing the test sample into an autoclave, set the temperature to 130℃ and the pressure to 2 atmospheres, heat to 130℃ and keep warm for 30 minutes. After cooling, take it out and observe its appearance and the precipitation state of the defoamer. The more severe the precipitation, the worse the stability.

[0057] Table 2 shows the high-temperature and high-pressure stability test results of Examples 1-4 and Comparative Examples 1-2. More positive signs indicate more severe precipitation, while fewer positive signs indicate a more stable defoamer and better high-temperature and high-pressure resistance. Compared to Comparative Example 2, the defoamer in each example and Comparative Example 1 showed less precipitation and more stable emulsions.

[0058] Table 2 Comparison of precipitation effects between the examples and comparative examples

[0059]

[0060] 2. Foam suppression and defoaming performance test

[0061] The testing method is as follows:

[0062] (1) Add 5g of sodium dodecylbenzenesulfonate, 5g of TX-100 and 2g of sodium hydroxide to 1000ml of tap water to prepare a foaming solution for later use.

[0063] (2) Dilute the prepared defoamer to a solid content of 5% for later use;

[0064] (3) Take 50g of the prepared foaming liquid and put it into a 100ml transparent PP bottle. Accurately weigh and add 0.1g of diluted defoamer, tighten the cap, and preheat in a 60℃ water bath for 15 minutes.

[0065] (4) Place the small bottle on a vertical shaker and shake it up and down for 1 minute at a frequency of 400 rpm. After stopping, immediately start the stopwatch to record the time when the foam disappears. Repeat the shaking test multiple times.

[0066] Table 3 shows the defoaming and foam suppression test results of Examples 1-8 and Comparative Examples 1-2. Shorter times indicate better defoaming effects. With an increase in the number of tests, the defoaming time did not significantly increase, indicating better durability and foam suppression performance of the defoamer. The results show that Examples 1-4 exhibited better defoaming and foam suppression performance and were more stable and resistant to degradation.

[0067] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A silicone emulsion defoamer for textiles, characterized in that, It is prepared by weight percentage from the following components: 5%-40% polysiloxane silicone paste, 0.3%-20% silicone polyether, 1%-20% emulsifier, 0.1%-5% thickener, 0.05%-0.3% bactericide, and the balance being water, with the sum of the weight percentages of all components being 100%. The polysiloxane silicone paste is a high-viscosity organosilicon composition, which is made of polyorganosiloxane, fumed silica, silicone resin and catalyst through a certain process. Its dynamic viscosity at 25°C is 400,000 to 800,000 mPa·s. The structural formula of the silicone polyether is as follows: Where R is a hydrogen atom, methyl, ethyl, propyl or butyl; subscript x is an integer from 1 to 50, y is an integer from 30 to 500, z is an integer from 1 to 50, p is an integer from 50 to 500; subscripts n and m are both integers from 1 to 50, and q is an integer from 1 to 8.

2. The silicone emulsion defoamer for textiles according to claim 1, characterized in that, It is prepared by weight percentage from the following components: 10%-35% polysiloxane silicone paste, 1%-15% silicone polyether, 2%-13% emulsifier, 0.1%-5% thickener, 0.05%-0.3% bactericide, and the balance being water, with the sum of the weight percentages of each component being 100%.

3. The silicone emulsion defoamer for textiles according to claim 1, characterized in that: in, The polyorganosiloxane is selected from polyvinylsiloxane (PEOS) or polymethylsiloxane (PMOS).

4. The silicone emulsion defoamer for textiles according to claim 1, characterized in that: in, The emulsifier is selected from one or more of nonionic surfactants and anionic surfactants; The nonionic surfactant is selected from any one of fatty acid polyoxyethylene ether, fatty alcohol polyoxyethylene ether, sorbitol, and castor oil polyoxyethylene ether; The anionic surfactant is selected from any one of sodium lauryl polyoxyethylene ether sulfate, 3-acylglycerol-1,2-disulfate salt, sodium dodecyl sulfate, sodium potassium lauryl sulfonate, sodium ethylhexanol succinate sulfonate, sodium N,N-oleoylmethyl taurate, sodium butylnaphthalene sulfonate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium hexadecyl sulfonate, and sodium dodecyl diphenyl ether disulfonate.

5. The silicone emulsion defoamer for textiles according to claim 1, characterized in that: in, The thickener is selected from any of the polyacrylate thickeners.

6. The method for preparing the silicone emulsion defoamer for textiles according to claim 1 or 2, characterized in that, Includes the following steps: (1) Add the formulated amount of polysiloxane silicone paste, silicone polyether, emulsifier and thickener to the emulsification kettle, stir at 55℃-65℃ for 1-3 hours, mix evenly, and the stirring speed is 100-800 rpm. (2) Cool down to 20℃-40℃, slowly add water, and emulsify at high speed of 800rpm-2000rpm; (3) Reduce the speed, add bactericide, and continue stirring at 100rpm-300rpm for 10-20 minutes to obtain the defoamer emulsion.

Images