A modified silica sol, its preparation method and application

Abstract

The present invention discloses a modified silica sol, a preparation method thereof and an application. Among them, the modified silica sol comprises the following components by weight ratio: 100 parts of water glass, 5 - 40 parts of sodium 3-chloro-2-hydroxypropanesulfonate, 30 - 300 parts of H-type cation exchange resin, and 100 - 2000 parts of deionized water; the preparation method includes preparing raw materials, preparing a silicic acid-containing solution, preparing a reaction solution, and preparing a sulfonated modified silica sol. The preparation route of the modified silica sol of the present invention is simple, with low energy consumption cost and no solvent pollution. While ensuring the water filtration and retention performance, the modified silica sol has good self-stability, can extend the storage period, and can also be applied to various papermaking environments.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking, and particularly to a modified silica sol, a preparation method thereof, and an application thereof. Background Art

[0002] Silica sol is a dispersion of nanoscale silicon dioxide particles in water or a solvent, and has advantages such as uniform particles, non-toxic and pollution-free, large specific surface area, high reaction activity, strong adsorption capacity and bonding performance, and is widely used in many industries such as architectural coatings, precision casting, refractory materials, catalyst carriers, and papermaking. Among them, in the papermaking industry, the use of silica sol can effectively improve the water filtration and retention rate in the papermaking process, and improve the paper formation and printing suitability. However, conventional silica sol has poor stability and is prone to gel during storage, and its application effect is not good in an acidic papermaking environment.

[0003] At present, relevant literature has recorded that modifying silica sol with sulfonic acid groups can improve the stability and application range of silica sol. However, the existing preparation process of sulfonic acid group-modified silica sol is complex, energy-consuming, and mostly has problems of solvent pollution and high cost. Summary of the Invention

[0004] To overcome the above disadvantages, the purpose of the present invention is to provide a modified silica sol, a preparation method thereof, and an application thereof, with a simple preparation route, low energy consumption cost, and no solvent pollution. After modification, the silica sol has good stability while ensuring water filtration and retention performance, can extend the storage period, and can also be applied to various papermaking environments.

[0005] One of the technical solutions adopted by the present invention to achieve the above purpose is: a modified silica sol, calculated by weight ratio, includes the following components:

[0006]

[0007]

[0008] The beneficial effect of the modified silica sol of the present invention is as follows:

[0009] Sodium 3-chloro-2-hydroxypropane sulfonate contains both a hydrophilic sulfonate group and a highly active halogen atom. In the alkaline environment provided by water glass, the halogen atom can react with the active silicon hydroxyl group to directly introduce the sulfonic acid group into the silica sol to obtain a modified silica sol, thereby achieving the effect of improving the storage stability of the silica sol and extending the storage period. Moreover, the modified silica sol can be better applied to alkaline and acidic papermaking environments.

[0010] Furthermore, it further includes 0-2 parts of a surfactant. On the basis of modifying silica sol with sulfonic acid groups, the comprehensive application performance of silica sol can be further enhanced by compounding with a surfactant.

[0011] Furthermore, the surfactant includes at least one of sodium dodecylbenzenesulfonate, lauryl betaine, coconut oil amide propyl betaine, etc.

[0012] Furthermore, the Baumé degree of the sodium silicate solution is 35 - 45. Sodium silicate solution is an aqueous solution of sodium silicate, a soluble silicate product composed of different proportions of alkali metal (sodium) and quartz sand (SiO2), and its typical molecular formula is Na2O·nSiO2·xH2O.

[0013] Furthermore, in the modified silica sol, the content of SiO2 is 5 - 25%, and the average particle size is 5 - 150 nm.

[0014] The second technical solution adopted by the present invention is: a preparation method of modified silica sol, comprising the following steps:

[0015] Prepare raw materials: Weigh sodium silicate solution, 3 - chloro - 2 - hydroxypropane sulfonate, H - type cation exchange resin, and deionized water respectively according to certain weight parts;

[0016] Prepare a silicic acid - containing solution: Take 1 / 5 - 1 / 2 of the sodium silicate solution, and dilute it with deionized water to make the content of SiO2 5 - 25%, then mix and stir it with a certain amount of H - type cation exchange resin at room temperature to obtain an aqueous solution containing silicic acid;

[0017] Prepare a reaction solution: Add the remaining sodium silicate solution, H - type cation exchange resin, deionized water, and 3 - chloro - 2 - hydroxypropane sulfonate into a reactor, and fully react under stirring to obtain a reaction solution;

[0018] Prepare sulfonated modified silica sol: Slowly add the aqueous solution containing silicic acid into the reaction solution, heat up to 30 - 70 °C and keep it warm for 1 - 5 h, and after filtration, the modified silica sol is obtained.

[0019] The beneficial effect of the preparation method of the present invention lies in:

[0020] According to the principle of the ion - exchange method, during the preparation, the silica sol is modified by 3 - chloro - 2 - hydroxypropane sulfonate, and the sulfonic acid group is introduced into the silica sol, which not only extends the storage period of the silica sol product, expands the application range of silica sol in papermaking, but also has a simpler reaction path, low energy consumption cost, and no solvent pollution during the reaction process.

[0021] Furthermore, during the process of slowly adding the aqueous solution containing silicic acid into the reaction solution, the addition time is controlled to be 0.1 - 3 h.

[0022] Furthermore, after the modified silica sol is prepared, a surfactant can be added and stirred to obtain a compounded modified silica sol.

[0023] When the above-mentioned modified silica sol is applied to a papermaking system, it can effectively improve the water filtration and retention rate and improve the formation of the paper. Specific Embodiments

[0024] The preferred embodiments of the present invention will be described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the scope of protection of the present invention more clearly defined.

[0025] A modified silica sol, by weight, comprises the following components: 100 parts of water glass, 5 - 40 parts of 3-chloro-2-hydroxypropanesulfonic acid sodium salt, 30 - 300 parts of H-type cation exchange resin, and 100 - 2000 parts of deionized water. The modified silica sol is prepared by the following preparation method:

[0026] (1) Prepare raw materials: Weigh water glass, 3-chloro-2-hydroxypropanesulfonic acid sodium salt, H-type cation exchange resin, and deionized water respectively according to the above weight parts;

[0027] (2) Prepare a silicic acid-containing solution: Take 1 / 5 - 1 / 2 of the water glass according to the weight part of the water glass in step (1), and dilute it with deionized water to a SiO2 content of 5 - 25%, then add a certain amount of H-type cation exchange resin and mix and stir at room temperature to obtain an aqueous solution containing silicic acid;

[0028] (3) Prepare a reaction solution: Add the remaining 1 / 2 - 4 / 5 weight parts of water glass, H-type cation exchange resin, deionized water, and 3-chloro-2-hydroxypropanesulfonic acid sodium salt to a reactor, and fully react under stirring to obtain a reaction solution;

[0029] (4) Prepare sulfonated modified silica sol: Slowly add the silicic acid-containing aqueous solution in step (2) to the reaction solution in step (3) within 0.1 - 3 h, heat up to 30 - 70 °C and keep warm for 1 - 5 h, and after filtration, the modified silica sol is obtained. Among them, in the modified silica sol, the SiO2 content is 5 - 25%, and the average particle size is 5 - 150 nm.

[0030] It should be noted that water glass is an aqueous solution of sodium silicate, which is a soluble silicate and is a product composed of alkali metals (sodium) and quartz sand (SiO2) in different proportions. Its typical molecular formula is Na2O·nSiO2·xH2O. In this embodiment, the Baume degree of water glass is 35 - 45, preferably 40.

[0031] In some embodiments, in step (2), the dosage ratio of the H-type cation exchange resin to the sodium silicate is 0.4-2:1.

[0032] In some embodiments, in order to further improve the application performance of the modified silica sol in papermaking, the comprehensive product stability and application effect can be achieved by compounding surfactants. It should be noted that the surfactant is added in an external form when using the silica sol. When adding, the surfactant and the modified silica sol are mixed and stirred evenly. Commonly used surfactants include at least one of sodium dodecylbenzenesulfonate, lauryl betaine, and coconut oil amide propyl betaine.

[0033] Example 1

[0034] Weigh 100 g of sodium silicate, 10 g of 3-chloro-2-hydroxypropane sulfonate, 180 ml of H-type cation exchange resin, and 100 g of deionized water respectively;

[0035] Take 50 g of sodium silicate and add it to 50 g of deionized water for dilution, and then stir it at room temperature with 80 ml of H-type cation exchange resin for 1 h to obtain an aqueous solution containing silicic acid;

[0036] Add the remaining 50 g of sodium silicate, 100 ml of H-type cation exchange resin, 50 g of deionized water, and 10 g of 3-chloro-2-hydroxypropane sulfonate to the reactor, and fully react under stirring to obtain a reaction solution;

[0037] Slowly add the aqueous solution containing silicic acid to the reactor within 1 h, heat up to 50 °C, and keep it warm for 2 h. After filtration, sample 1 is obtained. Among them, the SiO2 content of sample 1 is about 14%, and the particle size is about 50 nm.

[0038] Example 2

[0039] Weigh 100 g of sodium silicate, 5 g of 3-chloro-2-hydroxypropane sulfonate, 180 ml of H-type cation exchange resin, and 100 g of deionized water respectively;

[0040] Take 30 g of sodium silicate and add it to 30 g of deionized water for dilution, and then stir it at room temperature with 60 ml of H-type cation exchange resin for 1 h to obtain an aqueous solution containing silicic acid;

[0041] Add the remaining 70 g of sodium silicate, 120 ml of H-type cation exchange resin, 70 g of deionized water, and 5 g of 3-chloro-2-hydroxypropane sulfonate to the reactor, and fully react under stirring to obtain a reaction solution;

[0042] The aqueous solution containing silicic acid was slowly added to the reactor within 10 min, and the temperature was raised to 60 °C and kept warm for 1 h. After filtration, Specimen 2 was obtained. Among them, the SiO2 content of Specimen 2 was about 14%, and the particle size was about 80 nm.

[0043] Example 3

[0044] Weigh 100 g of water glass, 15 g of 3-chloro-2-hydroxypropanesulfonic acid sodium salt, 160 ml of H-type cation exchange resin, and 130 g of deionized water respectively;

[0045] Take 40 g of water glass and add it to 80 g of deionized water for dilution, and then stir it with 80 ml of H-type cation exchange resin at room temperature for 1.5 h to obtain an aqueous solution containing silicic acid;

[0046] Add the remaining 60 g of water glass, 80 ml of H-type cation exchange resin, 50 g of deionized water, and 15 g of 3-chloro-2-hydroxypropanesulfonic acid sodium salt to the reactor, and fully react under stirring to obtain a reaction solution;

[0047] The aqueous solution containing silicic acid was slowly added to the reactor within 1 h, and the temperature was raised to 50 °C and kept warm for 1 h. After filtration, Specimen 3 was obtained. Among them, the SiO2 content of Specimen 3 was about 13%, and the particle size was about 30 nm.

[0048] Example 4

[0049] Take Specimen 3 prepared in Example 3, and add 0.8% of sodium dodecylbenzenesulfonate, and stir it at room temperature for 1 h to obtain Specimen 4.

[0050] Example 5

[0051] Take Specimen 2 prepared in Example 2, add 0.3% of lauryl betaine, and stir it at room temperature for 1 h to obtain Specimen 5.

[0052] Application Example

[0053] Apply Specimens 1-5 prepared in Examples 1-5 to chemical pulp for performance testing, and compare them with the blank (without adding silica sol), commercial product 1 (conventional silica sol), and commercial product 2 (sulfonic acid group-modified silica sol). Among them, the addition amount of the specimen was 5 kg of stock solution / t of pulp, and the drainage was tested by a Canadian freeness tester, and the drainage amounts at static 5 s, 10 s, and 20 s were evaluated. Table 1 shows the results of the drainage and retention performance tests.

[0054] Table 1 Drainage and first-pass retention rate

[0055]

[0056]

[0057] As can be seen from Table 1, for Samples 1-5 prepared by the preparation method of the present invention, compared with the blank and commercially available products, the water filtration speed is accelerated, the first-pass retention rate is increased, and better retention and filtration aid performance is achieved.

[0058] In summary, the present invention uses sodium 3-chloro-2-hydroxypropanesulfonate to modify silica sol. Since sodium 3-chloro-2-hydroxypropanesulfonate contains both hydrophilic sulfonate groups and highly reactive halogen atoms, in the alkaline environment provided by water glass, the halogen atoms can react with reactive silicon hydroxyl groups to directly introduce sulfonic acid groups into the silica sol, thereby obtaining modified silica sol, so as to improve the storage stability of silica sol and extend the shelf life. Moreover, the reaction preparation process route is simple, the energy consumption cost is low, there is no solvent pollution, and its shelf life is greatly extended; subsequently, by compounding anionic or amphoteric betaine surfactants, comprehensive product stability and application effects can be achieved. When applied to various papermaking systems, as an important component in binary or multi-component particulate retention and filtration aids, it can effectively improve water filtration and retention rates and improve the paper formation.

[0059] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it, and should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A modified silica sol, characterized in that, Comprising the following components by weight ratio: The preparation method of modified silica sol comprises the following steps: Prepare raw materials: Weigh water glass, sodium 3-chloro-2-hydroxypropanesulfonate, H-type cation exchange resin, and deionized water respectively according to certain weight parts; Prepare the silicic acid-containing solution: Take 1 / 5 - 1 / 2 of the water glass, and dilute it with deionized water to a SiO2 content of 5 - 25%, then mix and stir it with a certain amount of H-type cation exchange resin at room temperature to obtain an aqueous solution containing silicic acid; Prepare the reaction solution: Add the remaining water glass, H-type cation exchange resin, deionized water, and sodium 3-chloro-2-hydroxypropanesulfonate into the reactor, and fully react under stirring to obtain the reaction solution; Prepare sulfonated modified silica sol: Slowly add the silicic acid-containing aqueous solution into the reaction solution, heat up to 30 - 70 °C and keep it warm for 1 - 5 h, after filtration, the modified silica sol is obtained.

2. The modified silica sol according to claim 1, wherein It also includes 0 - 2 parts of surfactant.

3. The modified silica sol according to claim 2, characterized in that, The surfactant includes at least one of sodium dodecylbenzenesulfonate, lauryl betaine, and coconut oil amide propyl betaine.

4. The modified silica sol according to claim 1, wherein The Baume degree of the water glass is 35 - 45.

5. The modified silica sol according to claim 1, characterized in that, In the modified silica sol, the SiO2 content is 5 - 25%, and the average particle size is 5 - 150 nm.

6. The preparation method of the modified silica sol according to claim 1, characterized in that, Comprises the following steps: Prepare raw materials: Weigh water glass, sodium 3-chloro-2-hydroxypropanesulfonate, H-type cation exchange resin, and deionized water respectively according to certain weight parts; Prepare the silicic acid-containing solution: Take 1 / 5 - 1 / 2 of the water glass, and dilute it with deionized water to a SiO2 content of 5 - 25%, then mix and stir it with a certain amount of H-type cation exchange resin at room temperature to obtain an aqueous solution containing silicic acid; Prepare the reaction solution: Add the remaining water glass, H-type cation exchange resin, deionized water, and sodium 3-chloro-2-hydroxypropanesulfonate into the reactor, and fully react under stirring to obtain the reaction solution; Prepare sulfonated modified silica sol: Slowly add the silicic acid-containing aqueous solution into the reaction solution, heat up to 30 - 70 °C and keep it warm for 1 - 5 h, after filtration, the modified silica sol is obtained.

7. The preparation method according to claim 6, characterized in that, During the process of slowly adding the silicic acid-containing aqueous solution into the reaction solution, control the addition time to be 0.1 - 3 h.

8. The preparation method according to claim 6, characterized in that, After obtaining the modified silica sol, a surfactant can also be added for stirring and mixing to obtain the compounded modified silica sol.

9. The application of the modified silica sol according to any one of claims 1 - 5 in papermaking.

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