Water-based organosilicon polymer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high-molecular compounds, and discloses a water-based organosilicon polymer as well as a preparation method and application thereof. Wherein the water-based organosilicon polymer is formed by polymerizing a silicon-containing oligomer a, a silicon-containing oligomer b and a cationic monomer. The water-based organosilicon polymer is high in water solubility and excellent in base material adsorbability, and can endow a base material with excellent water and oil repellency. The preparation process is simple and convenient, controllable in cost and suitable for large-scale industrial production, and has good popularization and application prospects.

Description

Technical Field

[0001] This invention relates to the field of polymer compound technology, specifically to an aqueous organosilicon polymer, its preparation method, and its application. Background Technology

[0002] With technological advancements and increased environmental awareness, pulp molded products, due to their biodegradable and recyclable properties, are gradually replacing traditional plastic products and are widely used in industries such as industrial packaging, food packaging, consumer goods, medical devices, and agriculture. Pulp molded products for food packaging need to possess excellent waterproof and oil-repellent properties. Fluorinated compounds were once widely used as waterproof and oil-repellent additives, but representative substances (such as PFAS) pose a long-term pollution risk to ecosystems due to their difficulty in degradation and tendency to accumulate in the environment. Therefore, many countries and regions, including the EU and the US, have implemented strict restrictions on the production and use of fluorides, promoting the development and application of non-fluorinated additives.

[0003] Existing non-fluorinated water and oil repellent agents mainly include wax-based additives, silicone additives, fatty acid derivatives, starch or cellulose-based modified materials, polyester materials, nanomaterials, and bio-based polymers. Among them, silicone materials, due to the high stability of their silicon-oxygen bonds (Si-O) and the low surface energy of their silane groups, can form a dense protective layer on the surface of paper or fibers, thus providing excellent water and oil repellency. Furthermore, silicone materials are environmentally friendly and non-toxic, and are considered an ideal alternative to fluorinated compounds.

[0004] In the prior art, JP2016102272A discloses a copolymer of silicone and acrylic acid, which can effectively improve the oil resistance of fibers while maintaining their softness and durability, but its water resistance is not evaluated. CN115521403A proposes an organosilicon polymer prepared by copolymerization of multiple monomers, exhibiting good water and oil repellency, but the raw materials are complex, some are costly, and the reaction time is long. When used as an in-slurry additive in pulp molding, this material needs to be combined with AKD, and its heat and oil resistance only reaches 85℃ / 20min, which cannot meet the national standard requirement of 95±3℃ / 30min. CN118359761A proposes a copolymer based on carbosiloxane dendritic monomers, whose special molecular structure endows the material with superior water and oil repellency. However, the preparation of this copolymer involves the precise addition of multiple monomers and additives, and requires strict control of free radical polymerization and quaternization steps, making the process complex and requiring high cost and quality control for industrial production. Furthermore, the organic solvents used in the polymerization process were not removed, which may pose environmental risks. Summary of the Invention

[0005] The purpose of this invention is to provide a water-based organosilicon polymer that has high water solubility, excellent substrate adsorption, and can impart excellent water and oil repellency to the substrate.

[0006] To achieve this objective, the present invention adopts the following technical solution: On the one hand, an aqueous organosilicon polymer is provided, which is polymerized from silicon-containing oligomer a, silicon-containing oligomer b and cationic monomer; The general structural formula of silicon-containing oligomer a is as follows: , R1 is an allyl ether group or a methacryloxy group; R2 is a C1-C1 group. 10 R3 is an alkyl group; R4 is a C1-C5 alkyl group, m=1-50; R5 is a polyether segment with the following structure: n = 1 - 20; The general structural formula of silicon-containing oligomer b is as follows: , R6 is a C1-C5 alkyl group; R7 is a C1-C5 alkyl group; R8, R9 and R 10 Selected from any one of hydroxyl, methoxy, or ethoxy, R8, R9, and R 10 Same or different; Among them, the cationic monomer is a quaternary ammonium salt type cationic monomer.

[0007] This invention utilizes silicon-containing oligomers to replace small-molecule monomers, significantly improving the film density of waterborne organosilicon polymers and thus enhancing their water and oil repellency. The introduction of hydrophilic polyether segments or amide groups into the silicon-containing oligomers improves the water solubility of the waterborne organosilicon polymer, resulting in better dispersibility in water and enabling uniform film formation on paper surfaces. The addition of cationic monomers enhances the adsorption capacity of the waterborne organosilicon polymer to paper fibers, allowing reactive functional groups in the polymer to covalently bond with the hydroxyl groups of cellulose molecules in the pulp, achieving a strong bond and improving durability. The main function of the cationic monomers is to impart a positive charge to the organosilicon copolymer, enabling it to adsorb onto the negatively charged fiber surface through electrostatic interactions. Simultaneously, the reactive groups in their molecules can covalently bond with the hydroxyl groups of cellulose molecules in the pulp, firmly binding the polymer to the fiber surface and forming a dense hydrophobic layer. This hydrophobic layer fills the gaps between the near-surface fiber networks of the pulp molded product, thereby reducing the possibility of water droplet penetration. Meanwhile, due to their low surface tension, silicon-containing molecular chains can orient themselves outwards, hindering the intrusion of oil molecules, thus giving pulp molded products excellent water and oil repellency.

[0008] Furthermore, R2 is a C1-C5 alkyl group.

[0009] Furthermore, R4 is a C1-C3 alkyl group.

[0010] Furthermore, m = 1-15.

[0011] Furthermore, n = 1-10.

[0012] Furthermore, R6 is a C1-C3 alkyl group.

[0013] Furthermore, R7 is a C1-C3 alkyl group.

[0014] Furthermore, the cationic monomer is selected from any one of dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, methacrylamidopropyl trimethyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, and allyl trimethyl ammonium chloride.

[0015] Furthermore, the mass percentages of silicon-containing oligomer a, silicon-containing oligomer b, and cationic monomer are 20-60%, 10-50%, and 5-30%, respectively, with a total mass percentage of 100%.

[0016] On the other hand, a method for preparing the aforementioned aqueous organosilicon polymer is provided, characterized by comprising the following steps: Silicon oligomer a, silicon oligomer b and cationic monomer are added to organic solvent and deionized water, stirred and heated to 60-80℃ in a nitrogen atmosphere, then potassium persulfate is added and kept at the temperature for 4-8 hours to allow the reaction to be complete. The organic solvent was removed to obtain a polymer. Then, deionized water at 45-65℃ was added to the polymer to adjust the pH, thus obtaining an aqueous organosilicon polymer.

[0017] The preparation process of this invention is simple and cost-controllable, suitable for large-scale industrial production, and has good prospects for promotion and application.

[0018] In another aspect, the application of the aforementioned aqueous organosilicon polymer in pulp molding products is provided, wherein the amount of the aqueous organosilicon polymer added is 2-5% based on the dry pulp used to prepare the pulp molding products.

[0019] The aqueous silicone polymer of this invention can be used directly as a stock solution, or it can be diluted with water or organic solvents as needed. Furthermore, this aqueous silicone polymer can be pre-mixed with other additives to optimize performance. Additive components include defoamers, pigments, thickening inhibitors, pH adjusters, surfactants, and crosslinking agents to meet different application requirements.

[0020] The beneficial effects of this invention are as follows: This invention uses silicon-containing oligomers to replace small-molecule monomers, which significantly improves the film-forming density of water-based organosilicon polymers, thereby enhancing their waterproof and oil-repellent properties. The introduction of hydrophilic polyether segments or amide groups into the silicon-containing oligomers improves the water solubility of the water-based organosilicon polymers, resulting in better dispersibility in water and enabling uniform film formation on paper surfaces. The addition of cationic monomers enhances the adsorption capacity of the water-based organosilicon polymers to paper fibers, allowing reactive functional groups in the water-based organosilicon polymers to undergo covalent bonding reactions with the hydroxyl groups of cellulose molecules in the pulp, achieving a strong bond and improving durability.

[0021] The preparation process of this invention is simple and cost-controllable, suitable for large-scale industrial production, and has good prospects for promotion and application. Detailed Implementation

[0022] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0023] Unless otherwise specified, all raw materials used in this invention are commercially available or can be prepared using conventional methods in this technical field.

[0024] The abbreviations and corresponding structural formulas of silicon-containing oligomer a, silicon-containing oligomer b, and cationic monomers are shown in Table 1.

[0025] Table 1. Abbreviations and corresponding structural formulas of silicon-containing oligomer a, silicon-containing oligomer b, and cationic monomers.

[0026] Example 1 In a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and reflux condenser, 15 g of silicon-containing oligomer aI, 10 g of silicon-containing oligomer bI, 5 g of cationic monomer cI, 10 g of deionized water, and 20 g of organic solvent were added. The mixture was slowly heated to 60-70°C under nitrogen atmosphere. Then, 0.45 g of potassium persulfate was added, and the reaction was maintained at this temperature for 6 hours. After the reaction was complete, the organic solvent was removed by vacuum distillation. Subsequently, 200 g of warm water (50°C) was slowly added to uniformly disperse the polymer. After cooling to room temperature, the pH was adjusted with lactic acid to obtain an aqueous organosilicon polymer P1 with a viscosity of 210 mPa·s, a solid content of approximately 18%, and a pH of 6.2.

[0027] Example 2 This embodiment is basically the same as Example 1, except that: the amount of silicon-containing oligomer aI is 30g, the amount of silicon-containing oligomer bI is 15g, and the amount of cationic monomer cI is 8g; the resulting waterborne organosilicon polymer P2 has a viscosity of 300mPa·s, a solid content of about 20%, and a pH value of 5.8.

[0028] Example 3 This embodiment is basically the same as Embodiment 1, except that: the amount of silicon-containing oligomer aI is 15g, the amount of silicon-containing oligomer bI is 20g, and the amount of cationic monomer cI is 12g; the resulting waterborne organosilicon polymer P3 has a viscosity of 150mPa·s, a solid content of about 19%, and a pH value of 6.5.

[0029] Example 4 This embodiment is basically the same as Example 1, except that: the silicon-containing oligomer a is a-II, and the amount used is 8g; the amount of silicon-containing oligomer bI is 20g, and the amount of cationic monomer cI is 12g; the resulting waterborne organosilicon polymer P4 has a viscosity of 105mPa·s, a solid content of about 16.5%, and a pH value of 5.5.

[0030] Example 5 This embodiment is basically the same as Example 1, except that: the amount of silicon-containing oligomer aI is 30g, the amount of silicon-containing oligomer bI is 30g; the cationic monomer c is c-II, and the amount is 5g; the resulting waterborne organosilicon polymer P5 has a viscosity of 230mPa·s, a solid content of about 24.5%, and a pH value of 6.6.

[0031] Example 6 This embodiment is basically the same as Example 1, except that: the silicon-containing oligomer a is a-III, the amount is 39g, the silicon-containing oligomer b is b-II, the amount is 7g, and the amount of cationic monomer cI is 19g; the resulting waterborne organosilicon polymer P6 has a viscosity of 170mPa·s, a solid content of about 19%, and a pH value of 6.5.

[0032] Example 7 This embodiment is basically the same as Example 1, except that: the silicon-containing oligomer a is a-II and the amount used is 25g; the silicon-containing oligomer b is b-II and the amount used is 25g; the amount of cationic monomer cI is 15g; the resulting waterborne organosilicon polymer P7 has a viscosity of 135mPa·s, a solid content of about 19%, and a pH value of 6.3.

[0033] Example 8 This embodiment is basically the same as Example 1, except that: the silicon-containing oligomer a is a-III and the amount used is 17g; the silicon-containing oligomer b is b-II and the amount used is 30g; the cationic monomer c is CI and the amount used is 18g; the resulting waterborne organic polymer P8 has a viscosity of 220mPa·s, a solid content of about 22%, and a pH value of 6.0.

[0034] Performance testing The aqueous organic polymers P1 to P8 prepared in Examples 1-8 above are miscible with water in any proportion, and the resulting diluted solutions are clear, transparent, and free of impurities.

[0035] 1. Preparation of plates Weigh out a 0.35% concentration, 23SR unbleached mixed pulp (sugarcane pulp and bamboo pulp, 7:3 ratio), and add the prepared water-based organosilicon polymers P1-P8 according to the weight of 10g dry pulp, with the addition amount based on 4% of the dry pulp. Stir for 5 minutes, let stand slightly, pour into a mold, vacuum suction to form a wet preform, and then transfer the wet preform to a hot press mold for drying. The drying conditions are vacuum suction, upper mold temperature 140℃, lower mold temperature 160℃, and baking time 90s. Press into an 8-inch round dinner plate with a thickness of 0.5mm.

[0036] 2. Water resistance test 2.1 Cobb value determination: The Cobb value of the plate samples was tested using a Cobb absorbency tester in accordance with GB / T 1540—2002.

[0037] 2.2 Hot Water Resistance Test: The plate samples were tested according to the requirements of GB / T 36787—2018. Hot water at (95±5)℃ was poured into the plate samples, and the samples were left to stand for 30 minutes. The plate samples were then observed for any deformation and for any seepage or leakage on the back. Condensation of water vapor at the bottom of the plate sample due to temperature differences between the inside and outside was not considered seepage or leakage.

[0038] 3. Oil resistance test 3.1 Kit rating test: The oil resistance rating (Kit value) of the plate samples was tested in accordance with the requirements of GB / T 22805.2—2002.

[0039] 3.2 Test the plate samples according to the requirements of GB / T 36787—2018. Pour hot oil at (95±5)℃ into the sample, let it stand for 30 min, and observe whether the plate sample is deformed and whether oil marks appear on the back of the plate sample.

[0040] The results of the water resistance and oil resistance tests are shown in Table 2.

[0041] Table 2. Performance Test Results

[0042] As shown in Table 2, the Kit values ​​of all the obtained plate samples were 7 or higher, and the Cobb values ​​were less than 25 g / m³. 2 It also has good resistance to heat oil and hot water.

[0043] The above embodiments are only used to illustrate the detailed method of the present invention. The present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A water-based organosilicon polymer, characterized in that, It is polymerized from silicon-containing oligomer a, silicon-containing oligomer b, and cationic monomers; The general structural formula of silicon-containing oligomer a is as follows: ， R1 is an allyl ether group or a methacryloxy group; R2 is a C1-C1 group. 10 R3 is an alkyl group; R4 is a C1-C5 alkyl group, m=1-50; R5 is a polyether segment with the following structure: n = 1 - 20; The general structural formula of silicon-containing oligomer b is as follows: ， R6 is a C1-C5 alkyl group; R7 is a C1-C5 alkyl group; R8, R9 and R 10 Selected from any one of hydroxyl, methoxy, or ethoxy, R8, R9, and R 10 Same or different; Among them, the cationic monomer is a quaternary ammonium salt type cationic monomer.

2. The aqueous organosilicon polymer according to claim 1, characterized in that, R2 is a C1-C5 alkyl group.

3. The aqueous organosilicon polymer according to claim 1, characterized in that, R4 is a C1-C3 alkyl group.

4. The aqueous organosilicon polymer according to claim 1, characterized in that, m=1-15。 5. The aqueous organosilicon polymer according to claim 1, characterized in that, n=1-10。 6. The aqueous organosilicon polymer according to claim 1, characterized in that, R6 is a C1-C3 alkyl group.

7. The aqueous organosilicon polymer according to claim 1, characterized in that, R7 is a C1-C3 alkyl group.

8. The aqueous organosilicon polymer according to claim 1, characterized in that, The cationic monomer is selected from any one of dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, methacrylamidopropyl trimethyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, and allyl trimethyl ammonium chloride.

9. The aqueous organosilicon polymer according to any one of claims 1 to 8, characterized in that, The mass percentages of silicon-containing oligomer a, silicon-containing oligomer b, and cationic monomer are 20-60%, 10-50%, and 5-30%, respectively.

10. A method for preparing the aqueous organosilicon polymer according to any one of claims 1 to 9, characterized in that, Includes the following steps: Silicon oligomer a, silicon oligomer b and cationic monomer are added to organic solvent and deionized water, stirred and heated to 60-80℃ in a nitrogen atmosphere, then potassium persulfate is added and kept at the temperature for 4-8 hours to allow the reaction to be complete. The organic solvent was removed to obtain a polymer. Then, deionized water at 45-65℃ was added to the polymer to adjust the pH, thus obtaining an aqueous organosilicon polymer.

11. The application of the aqueous organosilicon polymer according to any one of claims 1 to 9 in pulp molding products, characterized in that, Based on dry pulp used to prepare pulp molding products, the amount of water-based organosilicon polymer added is 2-5%.

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