A low molecular weight high content thickener and preparation method thereof

Abstract

The invention provides a low-molecular-weight and high-content thickener and a preparation method thereof. The thickener is mainly prepared from the following raw materials by weight: 110-130 parts of acrylic acid, 75-90 parts of caustic soda, 15-19 parts of sodium pyrosulfite, 15-19 parts of sodium sulfate, 7-12 parts of citric acid, 3-7 parts of ammonium persulfate, 3-7 parts of maleic anhydride, 0.8-2 parts of potassium persulfate and 220-260 parts of deionized water. The thickener effectively avoids the disadvantage that the high-content thickener cannot effectively control the chain growth process during synthesis to form implosion, resulting in the inability to stably control the viscosity.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical additives, in particular to a low-molecular-weight and high-content thickener and a preparation method thereof. Background Art

[0002] In the field of industrial water treatment, the effective dispersion of water treatment agents and their contact efficiency with pollutants in water are key links to ensure water purification. As an important component of water treatment agents, thickeners play a vital role in improving the stability and uniformity of agents. However, the thickeners currently used face challenges in many technologies and applications.

[0003] Most traditional thickeners are derived from natural materials. These natural thickeners are prone to lose their thickening effect under extreme conditions such as high temperature, acid and alkali, resulting in a decrease in the overall structural stability of the product. In addition, some natural thickeners have difficulties in dissolution and are prone to form lumps and particles, which not only affects the uniformity of the agent but also may reduce its treatment effect. At the same time, some natural thickeners are sensitive to electrolytes, and their performance may be significantly affected when the salt content in the water is high.

[0004] Although some high-performance natural thickeners can better meet the requirements of water treatment agents, their preparation costs are usually high, which undoubtedly increases production costs and limits wide applications. In order to overcome this problem, people began to explore the application of synthetic thickeners. However, most synthetic thickeners on the market are high molecular weight thickeners, which have too high a viscosity and are difficult to form a uniform solution with water treatment agents, thus affecting the dispersion effect and treatment capacity of the agents. On the other hand, although low-content thickeners can reduce viscosity, their molecular weight is too low, and the preparation process is difficult to control, making it difficult to achieve the required viscosity requirements.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide a low molecular weight and high content thickener. The significant advantage of the thickener is that it successfully solves the problem that chain growth is difficult to control during the synthesis of high-content thickeners, which is easy to cause explosion and polymerization, and then the viscosity cannot be stably adjusted. As an important additive for industrial water treatment agents, the thickener significantly improves the treatment efficiency in the water treatment process.

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned low molecular weight and high content thickener, which has a simple operation process and mild operating conditions, can achieve rapid preparation of products, and does not produce harmful substances in the entire preparation process, thereby realizing a green and environmentally friendly production process.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: A low-molecular-weight and high-content thickener is mainly prepared from the following raw materials, measured by weight: 110-130 parts of acrylic acid, 75-90 parts of caustic soda, 15-19 parts of sodium pyrosulfite, 15-19 parts of sodium sulfate, 7-12 parts of citric acid, 3-7 parts of ammonium persulfate, 3-7 parts of maleic anhydride, 0.8-2 parts of potassium persulfate and 220-260 parts of deionized water.

[0009] Preferably, as a further feasible scheme, in parts by mass: 115-128 parts of acrylic acid, 79-86 parts of caustic soda, 16-18 parts of sodium metabisulfite, 16-18 parts of glauber salt, 8-11 parts of citric acid, 4.5-6 parts of ammonium persulfate, 4-6 parts of maleic anhydride, 1-1.7 parts of potassium persulfate, and 230-242 parts of deionized water.

[0010] Preferably, as a further implementable scheme, in parts by mass: the low molecular weight and high content thickener according to claim 1, characterized in that, in parts by mass: 117 parts of acrylic acid, 84 parts of caustic soda, 17 parts of sodium metabisulfite, 17 parts of sodium sulfate, 10 parts of citric acid, 5 parts of ammonium persulfate, 5 parts of maleic anhydride, 1.3 parts of potassium persulfate, and 234 parts of deionized water.

[0011] Acrylic acid is used as the main raw material in the above raw materials, combined with other auxiliary ingredients to form a polymer system with excellent thickening effect; acrylic acid has good water solubility and film-forming properties, and can form a stable colloidal structure in water, thereby achieving efficient thickening.

[0012] As a reducing agent, sodium metabisulfite helps prevent the formation of oxidation byproducts during the polymerization process and maintain the stability of the polymer chain. As an electrolyte, sodium sulfate can affect the solubility of the polymer and the viscosity of the solution. The two work together to help adjust the rheological properties of the thickener, so that it can show good thickening performance under different conditions. As a chelating agent, citric acid can effectively complex metal ions in water and reduce their negative impact on the polymerization reaction. At the same time, citric acid can also adjust the pH value of the solution, and together with ammonium persulfate and potassium persulfate, it can start and accelerate the polymerization process of acrylic acid through redox reactions. Different dosage ratios of ammonium persulfate and potassium persulfate can finely control the polymerization rate and molecular weight distribution, thereby affecting the final performance of the thickener. The addition of maleic anhydride (maleic anhydride) introduces additional carboxyl functional groups to the polymer chain, which not only increases the polarity of the polymer chain, but also enhances the interaction between polymer molecules, which helps to improve the salt resistance and thermal stability of the thickener. In addition, the introduction of maleic anhydride promotes the dispersibility of the polymer in water, making it easier for the thickener to be evenly dispersed in the system.

[0013] As a solvent, deionized water not only provides the necessary reaction medium for the polymerization reaction, but also can affect the concentration of the polymer and the viscosity of the final product by precisely controlling its dosage. An appropriate amount of deionized water helps to form a uniform and stable polymer solution, ensuring that the thickener is easy to operate and apply during use.

[0014] In addition to providing the above-mentioned formula of a low molecular weight and high content thickener, the present invention also provides a method for preparing a low molecular weight and high content thickener, comprising the following steps: Add citric acid, sodium sulphate, maleic anhydride, sodium pyrosulfite and deionized water into the reaction kettle and stir until completely dissolved; Add ammonium persulfate and potassium persulfate into deionized water until they are completely dissolved, then add acrylic acid and mix evenly, then slowly drip it into the reactor, stop stirring and keep warm; Then, the flake caustic soda is dissolved in deionized water and then slowly dripped into the reaction kettle for stirring and neutralization.

[0015] Preferably, after slowly dripping into the reaction kettle for stirring and neutralization, an alkaline solution is required to adjust the pH value to 8.0.

[0016] Preferably, in the step of adding citric acid, sodium sulphate, maleic anhydride, sodium pyrosulfite and deionized water into a reaction kettle and stirring until they are completely dissolved, the stirring speed of the reaction kettle is 40-43 rpm and the temperature is 49-51°C.

[0017] Preferably, the time for slowly dripping it into the reaction kettle is 85-95 minutes, and the insulation time is 55-65 minutes.

[0018] Preferably, in the step of slowly dripping into the reaction kettle for stirring and neutralizing, the stirring speed of the reaction kettle is 38-40 rpm.

[0019] The invention improves the production quality of a low molecular weight, high content thickener by precisely controlling various operating parameters during the preparation process. The preparation method is not only simple and easy to operate, and has low equipment requirements, but also has a wide range of raw material sources, and no by-products are generated during the entire production process; in addition, the thickener can resist the influence of external factors, avoid decomposition and deterioration, thereby ensuring that excellent performance is always maintained during use.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention successfully controls the molecular weight of the thickener at a relatively low level by synthesizing the raw materials, which not only ensures its good dispersibility and solubility in the solution, but also reduces the production cost and transportation difficulty. Low molecular weight thickener molecules are more likely to penetrate into the material to be thickened, thereby achieving a rapid and uniform thickening effect.

[0021] The raw materials in the present invention have greatly increased the content of effective ingredients in the thickener through a carefully designed production method and formula; under the same thickening effect, the thickener of the present invention has a smaller amount of use, thereby reducing the cost of use, and the high content of effective ingredients makes the thickening effect more stable and reliable, and is not easily affected by changes in environmental conditions. And by accurately controlling the ratio of raw materials and key parameters in the preparation process, the stable preparation of low molecular weight and high content thickeners is successfully achieved, which effectively avoids the implosion phenomenon caused by the uncontrolled chain growth process in the traditional synthesis method, and ensures the stability and controllability of the viscosity of the thickener.

[0022] The thickener of the present invention is synthesized with environmentally friendly and non-toxic raw materials, does not contain harmful substances, and is harmless to human body and environment; during the production and use process, no harmful waste is generated, and the requirements of green chemistry and sustainable development are met. DETAILED DESCRIPTION

[0023] 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.

[0024] Example 1 The specific preparation of low molecular weight and high content thickener is carried out according to the following steps: (1) Take 8g of citric acid, 15g of sodium sulphate, 6g of maleic anhydride, 15g of sodium pyrosulfite and 116g of deionized water, add them into a reactor, control the stirring speed at 40 rpm until they are completely dissolved, and raise the temperature to 49°C; (2) 6 g of ammonium persulfate and 1 g of potassium persulfate were added to a glass container containing 48 g of deionized water to dissolve. After the mixture was completely dissolved, 115 g of acrylic acid was added and mixed evenly. The mixed solution was slowly dripped into the reactor. The whole process took 85 min to ensure that the dripping was completed. After the dripping was completed, stirring was stopped and the mixture was kept at a constant temperature for 55 min. (3) Take 75g of caustic soda flakes and add them to a glass container containing 80g of deionized water to dissolve. After the caustic soda flakes are completely dissolved, slowly drip the caustic soda flake solution into the reactor at a stirring speed of 40 revolutions per minute for neutralization reaction. During the neutralization process, closely observe the reaction changes. When the liquid changes from milky white to colorless and transparent, it indicates that the neutralization reaction is complete. (4) Finally, use 32% concentration of liquid caustic soda to fine-tune the pH value of the reaction system until it reaches 8.0.

[0025] Example 2 The specific preparation of low molecular weight and high content thickener is carried out according to the following steps: (1) Take 11g of citric acid, 13g of sodium sulphate, 4g of maleic anhydride, 13g of sodium metabisulfite and 125g of deionized water, add them into a reactor and control the stirring speed to 43 rpm until they are completely dissolved. The temperature is raised to 51°C. (2) 4.5 g of ammonium persulfate and 2 g of potassium persulfate were added to a glass container containing 51 g of deionized water to dissolve. After the mixture was completely dissolved, 128 g of acrylic acid was added and mixed evenly. The mixed solution was slowly dripped into the reactor. The whole process took 95 min to ensure that the dripping was completed. After the dripping was completed, stirring was stopped and the mixture was kept at a constant temperature for 65 min. (3) Take 90g of caustic soda flakes and add them to a glass container containing 84g of deionized water to dissolve. After the caustic soda flakes are completely dissolved, slowly drip the caustic soda flake solution into the reactor at a stirring speed of 38 revolutions per minute for neutralization reaction. During the neutralization process, closely observe the reaction changes. When the liquid changes from milky white to light yellow and transparent, it indicates that the neutralization reaction is complete. (4) Finally, use 32% concentration of liquid caustic soda to fine-tune the pH value of the reaction system until it reaches 8.0.

[0026] Example 3 The specific preparation of low molecular weight and high content thickener is carried out according to the following steps: (1) Take 7g of citric acid, 19g of sodium sulphate, 3g of maleic anhydride, 19g of sodium metabisulfite and 110g of deionized water, add them into a reactor and control the stirring speed to 41 rpm until they are completely dissolved, and the temperature rises to 49°C; (2) 3 g of ammonium persulfate and 0.8 g of potassium persulfate were added to a glass container containing 40 g of deionized water to dissolve. After the mixture was completely dissolved, 110 g of acrylic acid was added and mixed evenly. The mixed solution was slowly dripped into the reactor. The whole process took 87 min to ensure that the dripping was completed. After the dripping was completed, stirring was stopped and the mixture was kept at a constant temperature for 62 min. (3) Take 79g of caustic soda flakes and add them to a glass container containing 70g of deionized water to dissolve. After the caustic soda flakes are completely dissolved, slowly drip the caustic soda flake solution into the reactor at a stirring speed of 40 revolutions per minute for neutralization reaction. During the neutralization process, closely observe the reaction changes. When the liquid changes from milky white to light yellow and transparent, it indicates that the neutralization reaction is complete. (4) Finally, use 32% concentration of liquid caustic soda to fine-tune the pH value of the reaction system until it reaches 8.0.

[0027] Example 4 The specific preparation of low molecular weight and high content thickener is carried out according to the following steps: (1) Take 12g of citric acid, 18g of sodium sulphate, 7g of maleic anhydride, 18g of sodium pyrosulfite and 103g of deionized water, add them into a reactor, control the stirring speed to 42 rpm until they are completely dissolved, and raise the temperature to 51°C; (2) 7 g of ammonium persulfate and 1.7 g of potassium persulfate were added to a glass container containing 52 g of deionized water to dissolve. After the mixture was completely dissolved, 110 g of acrylic acid was added and mixed evenly. The mixed solution was slowly dripped into the reactor. The whole process took 92 min to ensure that the dripping was completed. After the dripping was completed, stirring was stopped and the mixture was kept at a constant temperature for 65 min. (3) Take 86g of caustic soda flakes and add them to a glass container containing 75g of deionized water to dissolve. After the caustic soda flakes are completely dissolved, slowly drip the caustic soda flake solution into the reactor at a stirring speed of 39 revolutions per minute for neutralization reaction. During the neutralization process, closely observe the reaction changes. When the liquid changes from milky white to colorless and transparent, it indicates that the neutralization reaction is complete. (4) Finally, use 32% concentration of liquid caustic soda to fine-tune the pH value of the reaction system until it reaches 8.0.

[0028] Example 5 The specific preparation of low molecular weight and high content thickener is carried out according to the following steps: (1) Take 10g of citric acid, 17g of sodium sulphate, 5g of maleic anhydride, 17g of sodium pyrosulfite and 113g of deionized water, add them into a reactor, control the stirring speed at 40 rpm until they are completely dissolved, and raise the temperature to 50°C; (2) 5 g of ammonium persulfate and 1.3 g of potassium persulfate were added to a glass container containing 47 g of deionized water to dissolve. After the mixture was completely dissolved, 110 g of acrylic acid was added and mixed evenly. The mixed solution was slowly dripped into the reactor. The whole process took 90 min to ensure that the dripping was completed. After the dripping was completed, stirring was stopped and the mixture was kept at a constant temperature for 60 min. (3) Take 84g of caustic soda flakes and add them to a glass container containing 75g of deionized water to dissolve. After the caustic soda flakes are completely dissolved, slowly drip the caustic soda flake solution into the reactor at a stirring speed of 40 revolutions per minute for neutralization reaction. During the neutralization process, closely observe the reaction changes. When the liquid changes from milky white to colorless and transparent, it indicates that the neutralization reaction is complete. (4) Finally, use 32% concentration of liquid caustic soda to fine-tune the pH value of the reaction system until it reaches 8.0.

[0029] Comparative Example 1 The specific implementation method is consistent with Example 5, except that the mass fraction of acrylic acid is changed to 50 g.

[0030] Comparative Example 2 The specific implementation method is consistent with Example 5, except that the mass fraction of acrylic acid is changed to 170 g.

[0031] Comparative Example 3 The specific implementation method is consistent with Example 5, except that citric acid is replaced by acetic acid.

[0032] Experimental Example 1 The specific effects of the low molecular weight and high content thickeners obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated, and the specific results are shown in Table 1: The thickeners prepared in the above-mentioned embodiments and comparative examples of the present invention were added into water treatment agents to test their viscosity.

[0033] Table 1. Thickener viscosity test results

[0034] Based on the above data, we can draw the following conclusions: By comparing the examples with the comparative examples, it can be found that the low molecular weight and high content thickener obtained by the method of the present invention will affect the stability and viscosity of the thickener when the raw material components and ratios are different. Examples 1 to 5, as the core preparation examples of the present invention, show a relatively stable viscosity range, specifically between 1230 and 1350 mPa·s. Even if there are slight fluctuations, the overall viscosity stability is not affected. In particular, Example 5, by virtue of its "preferred ratio, stable performance" characteristics, has a viscosity value of 1265 mPa·s, which is neither too high nor too low, providing great convenience for practical applications.

[0035] In contrast, the viscosity performance of Comparative Examples 1 to 3 is quite different. The viscosity of Comparative Example 1 dropped significantly to 950 mPa·s, and the viscosity of Comparative Example 2 increased significantly to 1445 mPa·s, indicating that some adjustment of the formula or raw materials had a significant negative impact on the viscosity. The viscosity of Comparative Example 3 increased abnormally to 1480 mPa·s and 1455 mPa·s, which may be due to incorrect selection of raw materials during the preparation process. More importantly, the stability of these three comparative examples was unqualified, further highlighting the decisive influence of preparation parameters and raw material selection on the performance of thickeners.

[0036] 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 low molecular weight, high content thickener, characterized in that: The invention is mainly prepared from the following raw materials in parts by mass: 110-130 parts of acrylic acid, 75-90 parts of flake caustic soda, 15-19 parts of sodium pyrosulfite, 15-19 parts of sodium sulfate, 7-12 parts of citric acid, 3-7 parts of ammonium persulfate, 3-7 parts of maleic anhydride, 0.8-2 parts of potassium persulfate and 220-260 parts of deionized water.

2. The low molecular weight high content thickener according to claim 1, characterized in that In parts by mass: 115-128 parts of acrylic acid, 79-86 parts of flake caustic soda, 16-18 parts of sodium metabisulfite, 16-18 parts of sodium sulphate, 8-11 parts of citric acid, 4.5-6 parts of ammonium persulfate, 4-6 parts of maleic anhydride, 1-1.7 parts of potassium persulfate, and 230-242 parts of deionized water.

3. The low molecular weight high content thickener according to claim 1, characterized in that In parts by mass: 117 parts of acrylic acid, 84 parts of flake caustic soda, 17 parts of sodium metabisulfite, 17 parts of sodium sulphate, 10 parts of citric acid, 5 parts of ammonium persulfate, 5 parts of maleic anhydride, 1.3 parts of potassium persulfate, and 234 parts of deionized water.

4. A method for preparing a low molecular weight, high content thickener as claimed in any one of claims 1 to 3, characterized in that: The steps include: Add citric acid, sodium sulfate, maleic anhydride, sodium metabisulfite and deionized water into a reaction kettle and stir until completely dissolved; Add ammonium persulfate and potassium persulfate into deionized water until they are completely dissolved, then add acrylic acid and mix evenly, then slowly drip it into the reactor, stop stirring and keep warm; Then, the flake caustic soda is dissolved in deionized water and then slowly dripped into the reaction kettle for stirring and neutralization.

5. The method for preparing a low molecular weight and high content thickener according to claim 4, characterized in that: After slowly dripping into the reaction kettle for stirring and neutralization, an alkaline solution is required to adjust the pH value to 8.

0.

6. The method for preparing a low molecular weight and high content thickener according to claim 4, characterized in that: In the step of adding citric acid, sodium sulphate, maleic anhydride, sodium pyrosulfite and deionized water into a reaction kettle and stirring until they are completely dissolved, the stirring speed of the reaction kettle is 40-43 rpm and the temperature is 49-51°C.

7. The method for preparing a low molecular weight and high content thickener according to claim 4, characterized in that: The time for slowly dripping the mixture into the reaction kettle is 85-95 minutes, and the insulation time is 55-65 minutes.

8. The method for preparing a low molecular weight and high content thickener according to claim 4, characterized in that: In the step of slowly dripping into the reaction kettle for stirring and neutralizing, the stirring speed of the reaction kettle is 38-40 rpm.

Images