Silyl ether defoaming agent and preparation method thereof

Abstract

The invention provides a silyl ether defoaming agent and a preparation method thereof, and the defoaming agent is mainly prepared from the following raw materials in parts by mass: 7-11 parts of dimethyl siloxane, 4-12 parts of modified polyether, 1-7 parts of a catalyst, 3-5 parts of ethanol, 3-17 parts of fatty acid amide, 2-8 parts of diatomite, 2-8 parts of alkali liquor and 15-35 parts of deionized water. The defoaming agent is prepared by condensation reaction of dimethyl siloxane and modified polyether, has excellent hydrophobicity and low surface tension, and can be quickly spread on the surface of foam and destroy the stability of the foam. Therefore, quick defoaming and long-acting foam inhibition are realized, and meanwhile, good environmental protection property and wide applicability are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of defoamers, and in particular to a silicone ether defoamer and a preparation method thereof. Background Art

[0002] In the industrial production process, many processes will produce foam, which may not only affect the smooth progress of the production process, but also have an adverse impact on the environment. Therefore, it is particularly important to use defoamers to remove and inhibit the generation of foam. At present, the most widely used defoamers are mainly silicone defoamers and polyether defoamers, each of which has its own unique advantages and disadvantages.

[0003] Silicone defoamers are a type of siloxane-based compounds, usually composed of long-chain macromolecules composed of organic groups, silicon atoms and oxygen atoms. Silicone defoamers have excellent defoaming effects, low dosage, and can be used in a wide temperature range. Their surface tension is generally lower than that of water and general foaming liquids, which makes them more effective in defoaming. However, in certain specific environments, silicone defoamers may cause pollution and have adverse effects on certain materials. The silicone compounds in them may cause safety and environmental problems, so special attention should be paid during use and storage.

[0004] In contrast, polyether defoamers are relatively safe: they are often used in the pharmaceutical, food and other industries, and are relatively harmless to the human body and the environment. In certain specific application scenarios, polyether defoamers may have better applicability. However, the defoaming effect of polyether defoamers is not ideal: especially for some high-foam liquids, their defoaming effect may not be as good as that of silicone defoamers. They are easily washed away by water and cannot maintain the defoaming effect for a long time.

[0005] There is a need for a defoamer that combines the advantages of both defoamers.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The first purpose of the present invention is to provide a silicone ether defoamer, which achieves the effects of rapid defoaming and long-term foam suppression through the synergistic effect of silicone ether compounds with specific structures and functional additives, and at the same time has good environmental protection and wide applicability.

[0008] The second object of the present invention is to provide a method for preparing the above-mentioned silicone ether defoaming agent, which is simple and can achieve rapid preparation of products while being economical and environmentally friendly, thus achieving a green economy.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: The invention provides a silicone ether defoamer, which is mainly prepared from the following raw materials, measured by weight: 7-11 parts of dimethylsiloxane, 4-12 parts of modified polyether, 1-7 parts of catalyst, 2-6 parts of ethanol, 3-17 parts of fatty acid amide, 2-8 parts of diatomaceous earth, 2-8 parts of alkali solution and 15-35 parts of deionized water.

[0010] Preferably, as a further specific embodiment, 8-10 parts of dimethylsiloxane, 5-10 parts of modified polyether, 2-5 parts of catalyst, 3-5 parts of ethanol, 5-15 parts of fatty acid amide, 3-6 parts of diatomaceous earth, 3-6 parts of alkali solution, and 20-30 parts of deionized water.

[0011] Preferably, as a further specific embodiment, 9 parts of dimethylsiloxane, 8 parts of modified polyether, 3 parts of catalyst, 4 parts of ethanol, 10 parts of fatty acid amide, 4 parts of diatomaceous earth, 5 parts of alkali solution, and 25 parts of deionized water.

[0012] Dimethylsiloxane and modified polyether participate in the reaction as reactants, and the two generate products through condensation reaction. The contents of dimethylsiloxane and modified polyether are corresponding. When one component is excessive, it will inevitably lead to a decrease in the content of the other component, and finally the generated product will produce unnecessary by-products, thereby affecting the performance of the product. In the present invention, the modified polyether can be a polyether in which ethylene oxide (EO) and propylene oxide (PO) respectively form homopolymerized long chain segments and are arranged at intervals on the main chain, forming EPE type or PEP type polyether according to different block sequences; or ethylene oxide (EO) and propylene oxide (PO) are randomly arranged on the molecular chain, and the two monomers are randomly distributed on the main chain, and no monomer can form a separate long chain segment polyether on the molecular chain.

[0013] In the present invention, ethanol and fatty acid amide are used as functional regulators, which can make the silicone ether defoamer better miscible with the substance to be defoamed, and can make the silicone ether defoamer disperse more evenly in the substance to be defoamed, thereby improving the solubility and dispersibility of the defoamer, and finally achieving the purpose of improving the defoaming performance of the defoamer. At the same time, the present invention limits the dosage of the two. When ethanol or fatty acid amide is excessive, it will affect the reaction system, but reduce the solubility and dispersibility of the defoamer; and when the dosage of the two is less, the improvement of the reaction system is limited, which will also cause its solubility and dispersibility to decrease, making it difficult for the defoamer to exist uniformly and stably in the substance to be defoamed, and the adaptability decreases, thereby affecting its defoaming and anti-foaming effects.

[0014] In the present invention, diatomaceous earth can stabilize the defoamer, prevent the defoamer from decomposing or precipitating during long-term storage or use, and has a certain antibacterial effect. In excess, it will not only cause unnecessary waste, but also make the defoamer too viscous.

[0015] Alkali solution will affect the cross-linking property of dimethylsiloxane. Adding an appropriate amount of alkali solution into the reaction system can promote the condensation reaction of dimethylsiloxane and modified polyether. Preferably, as a further specific embodiment, the catalyst is any one of sulfuric acid or a resin catalyst.

[0016] Preferably, as a further specific embodiment, the alkali solution is a sodium hydroxide solution; Preferably, the alkali solution is a 20wt%-30wt% sodium hydroxide solution; Preferably, the alkali solution is a 25wt% sodium hydroxide solution.

[0017] In the actual reaction process, sodium hydroxide or potassium hydroxide can be selected as the alkali solution to participate in the reaction. At the same time, its concentration and dosage need to be limited. When the alkali solution is excessive, the excess alkali solution will not promote the reaction; and the alkali solution itself has a certain corrosiveness, which not only causes waste but also easily pollutes the environment.

[0018] The present invention also provides a method for preparing the above-mentioned silicone ether defoamer, comprising the following steps: The dimethylsiloxane and the modified polyether are mixed, stirred and heated, and then a catalyst is added and stirred continuously to obtain a silyl ether main body; The silyl ether body is cooled, and ethanol and fatty acid amide are added and stirred for 25-35 minutes; Keep the temperature after cooling, add diatomaceous earth, and continue stirring for 1h-2h; Finally, add deionized water, cool to 25°C-35°C, and continue stirring to obtain the mixture.

[0019] Preferably, the stirring time is 30 min; Preferably, stirring is continued for 2 h; Preferably, the temperature is lowered to 25°C.

[0020] In the present invention, the reactants are first added to be fully mixed, and then a catalyst is added thereto to catalyze the reaction, and then a functional regulator is added to improve the reaction product, and finally diatomaceous earth is added to stabilize and thicken the product, and finally a portion of ionized water is added to adjust the defoamer.

[0021] Preferably, as a further specific embodiment, in the step of mixing, stirring and heating the modified polyether, the heating temperature is 117° C.-123° C.; Preferably, the heating temperature is 120°C.

[0022] Preferably, as a further specific embodiment, in the step of cooling the main body of the silyl ether, the cooling temperature is 40°C-50°C; Preferably, the cooling temperature is 45°C.

[0023] Preferably, as a further specific embodiment, in the step of cooling to 25°C-35°C and continuously stirring, the stirring time is 25min-35min; Preferably, the stirring time is 30 min.

[0024] Preferably, as a further specific embodiment, in the step of adding the catalyst and continuously stirring, the stirring time is 3h-4h; Preferably, the stirring time is 4 h.

[0025] In the present invention, the reaction temperature and stirring time are limited. On the one hand, too high a temperature will easily cause the reactants to decompose themselves, and the defoaming agent cannot be produced; on the other hand, too high a temperature will cause the reaction to be too violent, making the reaction difficult to control; finally, when the reaction temperature exceeds the limit value, unknown and difficult-to-separate organic matter is easily produced, and the defoaming agent cannot be obtained.

[0026] As for the stirring time, excessive stirring can easily lead to bubbles in the reaction system, thereby reducing the quality of the defoaming agent.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The defoamer of the present invention is prepared by condensation reaction of dimethylsiloxane and modified polyether, has excellent hydrophobicity and low surface tension, can quickly spread on the foam surface and destroy its stability, thereby achieving rapid defoaming and long-term foam suppression, and has good environmental protection and wide applicability.

[0028] (2) The preparation method of the present invention is simple and can effectively reduce environmental pollution while improving preparation efficiency and ensuring product stability. DETAILED DESCRIPTION

[0029] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0030] Example 1 7 g of dimethylsiloxane and 4 g of modified polyether were added to a reaction kettle, heated to 117° C., and then 1 g of sulfuric acid was added thereto, and stirred for 3 h to obtain a silyl ether main body; The silyl ether body was cooled to 40°C, 2 g ethanol and 3 g fatty acid amide were added to the reactor, and stirring was continued for 25 min; Maintaining the temperature at 40°C, add 3 g of 20 wt% sodium hydroxide solution and 3 g of diatomaceous earth into the reaction kettle and continue stirring for 1 hour; Finally, add 15 g of deionized water into the reactor and cool it to 25°C to obtain the product.

[0031] Example 2 11 g of dimethylsiloxane and 12 g of modified polyether were added to a reaction kettle, heated to 123° C., and then 7 g of sulfuric acid was added thereto, and stirred for 4 h to obtain a silyl ether main body; The silyl ether body was cooled to 50°C, 6 g of ethanol and 17 g of fatty acid amide were added to the reactor, and stirring was continued for 25 min; Maintaining the temperature at 40°C, add 8 g of 20 wt% sodium hydroxide solution and 8 g of diatomaceous earth into the reaction kettle and continue stirring for 1 hour; Finally, add 35 g of deionized water into the reactor and cool it to 35° C. to obtain the product.

[0032] Example 3 5 g of dimethylsiloxane and 2 g of modified polyether were added to a reaction kettle, heated to 120° C., and then 2 g of sulfuric acid was added thereto, and stirred for 4 h to obtain a silyl ether main body; The silyl ether body was cooled to 45°C, 3 g of ethanol and 5 g of fatty acid amide were added to the reactor, and stirring was continued for 25 min; Maintaining the temperature at 40°C, add 3g of 30wt% sodium hydroxide solution and 3g of diatomaceous earth into the reaction kettle and continue stirring for 2h; Finally, add 20 g of deionized water into the reactor and cool it to 25°C to obtain the product.

[0033] Example 4 5 g of dimethylsiloxane and 2 g of modified polyether were added to a reaction kettle, heated to 120° C., and then 2 g of sulfuric acid was added thereto, and stirred for 4 h to obtain a silyl ether main body; The silyl ether body was cooled to 45°C, 3 g of ethanol and 5 g of fatty acid amide were added to the reactor, and stirring was continued for 25 min; Maintaining the temperature at 40°C, add 3 g of 25 wt% sodium hydroxide solution and 3 g of diatomaceous earth into the reaction kettle and continue stirring for 2 h; Finally, add 20 g of deionized water into the reactor and cool it to 25°C to obtain the product.

[0034] Example 5 9 g of dimethylsiloxane and 8 g of modified polyether were added to a reaction kettle, heated to 120° C., and then 3 g of sulfuric acid was added thereto, and stirred for 4 h to obtain a silyl ether main body; The silyl ether body was cooled to 45°C, 4 g ethanol and 10 g fatty acid amide were added to the reactor, and stirring was continued for 25 min; Maintaining the temperature at 40°C, add 5 g of 25 wt% sodium hydroxide solution and 4 g of diatomaceous earth into the reaction kettle and continue stirring for 2 h; Finally, add 25 g of deionized water into the reactor and cool it to 25°C to obtain the product.

[0035] Example 6 The specific implementation method is consistent with Example 5, except that the catalyst is replaced with a resin catalyst of equal mass.

[0036] Example 7 The specific implementation method is consistent with Example 5, except that the concentration of the sodium hydroxide solution is changed to 45wt%.

[0037] Example 8 The specific implementation method is consistent with Example 5, except that the concentration of the sodium hydroxide solution is changed to 10wt%.

[0038] Example 9 The specific implementation method is consistent with Example 5, and the reaction conditions are changed, as shown in Table 1.

[0039] Table 1: Variation of reaction conditions

[0040] Comparative Example 1 The specific implementation method is consistent with Example 5, and the dosage of each substance is changed. The specific changes are shown in Table 2.

[0041] Table 2: Changes in dosage between various substances

[0042] Comparative Example 2 Choose a common defoaming agent available on the market, whose main components are emulsifier, carrier, emulsifying aid and active ingredient.

[0043] Experimental Example 1 Sodium lauryl sulfate, Tween 80 and lecithin were mixed in a ratio of 1:1:1, and then prepared into a 1% aqueous solution as a foaming solution; an air pump was used to ventilate 100 mL of the foaming solution in a 500 mL measuring cylinder in a constant temperature water bath at 50°C, with an air flow rate of 1000 mL / min. When the foam volume reached 500 mL, ventilation was stopped, and 0.1 g of defoaming agent was added to defoam, and the time from the addition of the agent to the disappearance of the foam was recorded, which was the defoaming time. Continue to blow air, and record the time when the foam reaches 500 mL again. At the same time, the stability of the prepared defoaming agent was tested.

[0044] The experimental results are shown in Tables 3 and 4.

[0045] Table 3: Experimental results of defoaming time and foam suppression time of the embodiment

[0046] Table 4: Experimental results of defoaming time and foam suppression time of comparative examples

[0047] Based on the above data, we can draw the following conclusions: Comparing Example 5 with Scheme 1 to Scheme 4 in Comparative Example 1, it can be seen that in the present invention, too much or too little of a certain component will affect the defoaming performance and anti-foaming performance of the defoamer. Dimethylsiloxane and modified polyether are both reactants of the present invention. Therefore, when the content of any component of either is too high, it may cause itself to decompose at high temperature, and the decomposed product will produce other uncontrollable reactions; this can be reflected from the experimental data. When the dosage of the two changes, the defoaming time and anti-foaming time of the generated defoamer become longer, which can reflect from the side that the product purity is not high, affecting the performance of the defoamer. In addition, due to the large number of impurities, the stability of the defoamer is also negatively affected.

[0048] Comparing Example 5 with Schemes 3 to 8 in Comparative Example 1, it can be seen that the functional additives can greatly affect the stability of the defoamer. It can be intuitively seen from the experimental data that when the above components change, the defoaming time will be prolonged and the antifoaming time will be reduced, and the stability will be reduced; the data can also reflect from the side that the above functional additives can adjust the performance of the defoamer itself, thereby achieving the purpose of improving its defoaming performance.

[0049] Ethanol and fatty acid amide can increase the solubility and dispersibility of the defoamer, so that the defoamer can form a uniform and stable phase with the substance to be defoamed, thereby improving the working efficiency of the defoamer and achieving the purpose of adjusting the performance of the defoamer itself.

[0050] Comparing Example 5 with Schemes 9-10 in Comparative Example 1, it can be seen that the selection of diatomaceous earth is mainly based on the long-term storage of the defoamer. When the defoamer is stored for a long time, adding diatomaceous earth can have a stabilizing effect on it, and can effectively prevent the defoamer from decomposing, precipitating or stratifying during long-term storage or use. It can also be seen from the experimental data that diatomaceous earth does not directly affect the performance of the defoamer, but directly affects its stability.

[0051] Comparing Example 5 with Scheme 11-Scheme 12 in Comparative Example 1, it is necessary to add an appropriate amount of alkali solution during the experiment to promote the condensation between dimethylsiloxane and polyether. When its content is low, the improvement on the condensation effect is low, resulting in a slightly longer defoaming time; although an excessive amount will not affect the reaction, it will cause unnecessary waste.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silicone ether defoamer, characterized in that: The invention is mainly prepared from the following raw materials by weight: 7-11 parts of dimethylsiloxane, 4-12 parts of modified polyether, 1-7 parts of catalyst, 2-6 parts of ethanol, 3-17 parts of fatty acid amide, 2-8 parts of diatomaceous earth, 2-8 parts of alkali solution and 15-35 parts of deionized water.

2. The silicone ether defoamer according to claim 1, characterized in that: 8-10 parts of dimethylsiloxane, 5-10 parts of modified polyether, 2-5 parts of catalyst, 3-5 parts of ethanol, 5-15 parts of fatty acid amide, 3-6 parts of diatomaceous earth, 3-6 parts of alkali solution, and 20-30 parts of deionized water.

3. The silicone ether defoamer according to claim 1, characterized in that: 9 parts of dimethylsiloxane, 8 parts of modified polyether, 3 parts of catalyst, 4 parts of ethanol, 10 parts of fatty acid amide, 4 parts of diatomaceous earth, 5 parts of alkali solution, and 25 parts of deionized water.

4. The silicone ether defoamer according to claim 1, characterized in that: The catalyst is any one of sulfuric acid or resin catalyst.

5. The silicone ether defoamer according to claim 1, characterized in that: The alkali solution is a sodium hydroxide solution; Preferably, the alkali solution is a 20wt%-30wt% sodium hydroxide solution; Preferably, the alkali solution is a 25wt% sodium hydroxide solution.

6. A method for preparing the silicone ether defoamer according to any one of claims 1 to 5, characterized in that: The steps include: The dimethylsiloxane and the modified polyether are mixed, stirred and heated, and then a catalyst is added and stirred continuously to obtain a silyl ether main body; The silyl ether body is cooled, and ethanol and fatty acid amide are added and stirred for 25-35 minutes; Keep the temperature after cooling, add diatomaceous earth, and continue stirring for 1h-2h; Finally, add deionized water, cool to 25°C-35°C, and continue stirring to obtain the mixture.

7. The method for preparing a silicone ether defoamer according to claim 6, characterized in that: In the step of mixing, stirring and heating the modified polyether, the heating temperature is 117° C.-123° C.

8. The method for preparing a silicone ether defoamer according to claim 6, characterized in that: In the step of cooling the main body of the silane, the cooling temperature is 40°C-50°C.

9. The method for preparing a silicone ether defoamer according to claim 6, characterized in that: In the step of cooling to 25°C-35°C and continuously stirring, the stirring time is 25min-35min.

10. The method for preparing a silicone ether defoamer according to claim 6, characterized in that: In the step of adding the catalyst and continuously stirring, the stirring time is 3h-4h.

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