Paper surface enhancing aid as well as preparation method and application thereof

Abstract

The invention discloses a paper surface enhancing auxiliary agent and a preparation method and application thereof, and is characterized in that the paper surface enhancing auxiliary agent comprises the following raw materials by weight: 1-10 parts of polyvinyl alcohol, 1-10 parts of a cationic monomer, 1-5 parts of an anionic monomer, 5-20 parts of vinylpyrrolidone, 1-12 parts of acrylamide and an active hydroxyl-containing monomer, 0.05-2 parts of an initiator, 0.05-2 parts of a reducing agent, and 1-10 parts of a cross-linking agent. 0-2 parts of mineral substances and 50-75 parts of water; the polyvinyl alcohol, the cationic monomer, the anionic monomer, the vinylpyrrolidone, the active hydroxyl-containing monomer and the like are polymerized, a chain segment with excellent toughness, film-forming property and binding property is introduced, and the surface reinforcing agent with permeability, surface film-forming property and strength performance is obtained through crosslinking of a silicon-containing product and a zirconium-containing product, so that the surface strength of a paper surface can be remarkably improved; the RI galling points on the paper surface are reduced, the interlayer bonding strength of the paper is improved, the fiber proportion is optimized, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of papermaking technology, specifically to a paper surface strengthening agent, its preparation method, and its application. Background Technology

[0002] In the printing and packaging industry, the surface strength of paper is a key factor affecting print quality. Insufficient surface strength can lead to problems such as powdering, smudging, fuzzing, and even paper breaks during the printing process, seriously affecting the image clarity, color reproduction, and production efficiency of printed materials, and ultimately damaging the image and market competitiveness of the final product.

[0003] Currently, the industry typically adds chemicals during the sizing process of paper to improve its surface strength. Commonly used surface strengthening agents are mostly modified polyacrylamide products. However, these products still have limitations in terms of covering power, toughness, and surface strength improvement, making it difficult to fully meet the stringent requirements of high-speed and high-quality printing for paper surface properties. Therefore, developing a novel surface strengthening agent that can significantly improve paper's dry and wet strength, surface roughness, and adaptability to different production conditions is of great significance for optimizing fiber ratios, reducing production costs, and improving paper quality. To this end, a paper surface strengthening agent, its preparation method, and its application are proposed. Summary of the Invention

[0004] The purpose of this invention is to solve the above problems by providing a paper surface strengthening agent, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention provides a paper surface strengthening agent, characterized in that it comprises raw materials with the following weight components: Polyvinyl alcohol: 1-10 parts, Cationic monomer: 1-10 parts Anionic monomer: 1-5 parts Vinylpyrrolidone: 5-20 parts, Acrylamide and monomers containing active hydroxyl groups: 1-12 parts, Initiator: 0.05-2 parts, Reducing agent: 0.05-2 parts, Crosslinking agent: 1-10 parts, Minerals: 0-2 parts Water: 50-75 parts.

[0006] More preferably, the polyvinyl alcohol is selected from at least one of 0588, 0599, 1788, 1792, 1799, 2088, 2099, 2488, and 2499; the cationic monomer includes at least one of methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, dimethyl diallyl ammonium chloride, acryloyl ethylenediamine hydrochloride, and N,N-dimethylaminopropyl ethyl methacrylate.

[0007] More preferably, the anionic monomer is selected from at least one of itaconic acid, acrylic acid, and methacrylic acid; the acrylamide and the monomer containing active hydroxyl groups are selected from at least one of N-(hydroxymethyl)acrylamide, N-hydroxyethylacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and acrylamide.

[0008] More preferably, the initiator is at least one of ammonium persulfate, potassium persulfate, and sodium persulfate; the reducing agent is at least one of sodium sulfite, sodium bisulfite, sodium dithionite, and sodium metabisulfite; the crosslinking agent is selected from at least one of modified silica, modified potassium zirconium carbonate, and modified ammonium zirconium carbonate; and the mineral is selected from at least one of modified wollastonite and organobentonite.

[0009] This invention provides a method for preparing a paper surface strengthening agent, characterized by comprising the following steps: S1. Add water and polyvinyl alcohol to the reaction apparatus, stir and heat to 80℃-95℃, and maintain for 0.5h-1.5h until completely dissolved; S2. At 80℃-95℃, add cationic monomers, anionic monomers, acrylamide and a mixture containing active hydroxyl monomers and vinylpyrrolidone dropwise, while simultaneously adding initiators and reducing agents. The dropwise addition time is 1h-5h, and the temperature is maintained for 0.5h-2h after the addition is complete. S3. Cool down to below 45℃, add crosslinking agent, react for 0.5h-1h to obtain the paper surface strengthening agent product; S4. Optionally, minerals are added during post-processing, stirred for 0.5-2 hours, filtered, and the paper surface strengthening agent is obtained.

[0010] This invention provides an application of a paper surface strengthening agent in papermaking.

[0011] The beneficial effects of this invention are as follows: By polymerizing polyvinyl alcohol, cationic monomers, anionic monomers, vinylpyrrolidone, and monomers containing active hydroxyl groups, segments with superior toughness, film-forming properties, and binding properties are introduced. Through crosslinking with silicon- and zirconium-containing products, a surface reinforcing agent is obtained that balances permeability, surface film-forming properties, and strength performance. This significantly improves the surface strength of paper, reduces paper surface ribbing points, enhances interlayer bonding strength, helps optimize fiber ratios, and reduces costs. Simultaneously, the addition of a small amount of mineral modification accelerates drying speed, adapts to different drying conditions, and the resulting paper fully meets performance requirements, resulting in energy conservation and emission reduction. Attached Figure Description

[0012] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0013] The present invention will be further described below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention.

[0014] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0015] Example 1: Paper surface strengthening agent finished product A In a reaction apparatus equipped with a stirrer, a dropping device, a reflux condenser, and a thermometer, add an appropriate amount of water, start stirring, add 8 parts of polyvinyl alcohol (0588), stir and heat to 85℃-90℃, keep warm for 0.5h until completely dissolved and homogeneous. The system was then cooled to 80°C, and a mixture of monomers (3 parts dimethyl diallyl ammonium chloride, 13 parts vinylpyrrolidone, 3 parts acrylamide, 5 parts 2-hydroxyethyl methacrylate, and 2 parts itaconic acid) was added dropwise. At the same time, 0.3 parts potassium persulfate (prepared as an aqueous solution) and 0.45 parts sodium metabisulfite (prepared as an aqueous solution) were added dropwise at 80°C-85°C for 2 hours. After the addition was completed, the system was kept at 85°C for 2 hours. Cool the temperature to below 45℃, add 5 parts of modified potassium zirconium carbonate, stir for 0.5 hours, and finally add water to adjust the total product to 100 parts to obtain paper surface strengthening agent product A.

[0016] Example 2: Paper surface strengthening agent finished product B In a reaction apparatus equipped with a stirrer, a dropping device, a reflux condenser, and a thermometer, add an appropriate amount of water, start stirring, add 5 parts of polyvinyl alcohol (1799), stir and heat to 85-90℃, keep warm for 1 hour until dissolved and uniform. Cool to 80℃, and add dropwise a mixture of monomers (5 parts methacryloyloxyethyltrimethylammonium chloride, 10 parts vinylpyrrolidone, 5 parts acrylamide, 5 parts 2-hydroxyethyl acrylate, and 3 parts acrylic acid), while simultaneously adding 0.4 parts ammonium persulfate (prepared as an aqueous solution) and 0.6 parts sodium bisulfite (prepared as an aqueous solution). Add the monomers dropwise at 80-85℃ for 2 hours, and then keep the temperature at 85℃ for 2 hours after the addition is complete. Cool the temperature to below 45℃, add 7 parts of modified silica, stir for 0.5 hours, and finally add water to adjust the total product to 100 parts to obtain paper surface strengthening agent product B.

[0017] Example 3: Paper surface strengthening agent finished product C In a reaction apparatus equipped with a stirrer, a dropping device, a reflux condenser, and a thermometer, add an appropriate amount of water, start stirring, add 6 parts of polyvinyl alcohol (1788), stir and heat to 85-90℃, keep warm for 1 hour until dissolved and uniform. Cool to 80℃, and add dropwise a mixture of monomers (3 parts N,N-dimethylaminopropyl ethyl methacrylate, 10 parts vinylpyrrolidone, 4 parts acrylamide, 4 parts 2-hydroxyethyl methacrylate, and 3 parts acrylic acid), while simultaneously adding 0.3 parts ammonium persulfate (prepared as an aqueous solution) and 0.45 parts sodium metabisulfite (prepared as an aqueous solution). Add the monomers dropwise at 80-85℃ for 2.5 hours, and after the addition is complete, keep the temperature at 85℃ for 1 hour. Cool the temperature to below 45℃, add 5 parts of modified zirconium carbonate, stir for 0.5 hours, and finally add water to adjust the total product to 100 parts to obtain paper surface strengthening agent product C.

[0018] Example 4: Paper surface strengthening agent finished product D In a reaction apparatus equipped with a stirrer, a dropping device, a reflux condenser, and a thermometer, add an appropriate amount of water, start stirring, add 7 parts of polyvinyl alcohol (1788), stir and heat to 85-90℃, keep warm for 1 hour until dissolved and uniform. Cool to 80℃, add dropwise a mixture of monomers (4 parts dimethyl diallyl ammonium chloride, 8 parts vinylpyrrolidone, 2 parts acrylamide, 4 parts N-(hydroxymethyl)acrylamide, 2 parts methacrylic acid), 0.25 parts sodium persulfate (prepared as an aqueous solution), and 0.4 parts sodium metabisulfite (prepared as an aqueous solution). Add dropwise at 80-85℃ for 2.5 hours. After the addition is complete, keep warm at 90℃ for 2 hours. Cool the temperature to below 45℃, add 6 parts of modified silica, stir for 0.5 hours, and finally add water to adjust the total product to 100 parts to obtain paper surface strengthening agent product D.

[0019] Example 5: Paper surface strengthening agent finished product E Take 100 parts of the finished product A obtained in Example 1, add 0.5 parts of modified wollastonite while stirring, and continue stirring for 0.5 hours to obtain the finished paper surface strengthening agent E.

[0020] Example 6: Paper surface strengthening agent finished product F Take 100 parts of the finished product A obtained in Example 1, add 1 part of organic bentonite while stirring, and continue stirring for 1 hour to obtain the finished product F of paper surface strengthening agent.

[0021] Example 7: Paper surface strengthening agent finished product G Take 100 parts of the finished product B obtained in Example 2, add 1.5 parts of modified wollastonite while stirring, and continue stirring for 1 hour to obtain the finished paper surface strengthening agent G.

[0022] The surface strengthening agents (A, B, C, D) prepared in Examples 1-4 were used in the surface sizing system for testing. The paper basis weight was 70g, and the addition amount was 2kg / t. The paper performance test results are listed in Table 1.

[0023] Table 1 Performance Test Results

[0024] Table 2 Performance at different drying temperatures

[0025] As shown in Table 1, after using the surface strengthening additives prepared in Examples 1-4 of the present invention, the IGT surface strength, wet strength and wax stick scratch grade of the paper were significantly improved compared with the blank sample, proving that the product of the present invention can effectively improve the overall surface physical strength of the paper.

[0026] As shown in Table 2, the products of this invention (including the basic AD and mineral-modified EG) can stably exert their reinforcing effect under both relatively low (90℃) and relatively high (105℃) drying conditions, and their performance indicators are significantly better than the blank control. In particular, after specific mineral modification (Examples 5, 6, and 7), the products exhibit more balanced performance under the two temperature differences, demonstrating good process adaptability and drying rate adaptability.

[0027] In summary, the paper surface strengthening agent provided by this invention, through unique raw material formulation and polymerization-crosslinking process, successfully prepares a high-performance product with excellent permeability, film-forming properties, strong adhesion, and drying adaptability. This product can significantly improve the dry / wet strength, surface strength, and printability of paper, helping to optimize production costs and possessing good prospects for industrial application.

[0028] The scope of protection of this invention is not limited to the above embodiments and their variations. Conventional modifications and substitutions made by those skilled in the art based on the content of these embodiments are all within the scope of protection of this invention.

Claims

1. A paper surface strengthening agent, characterized in that, Raw materials comprising the following weight components: Polyvinyl alcohol: 1-10 parts Cationic monomer: 1-10 parts Anionic monomer: 1-5 parts Vinylpyrrolidone: 5-20 parts Acrylamide and monomers containing active hydroxyl groups: 1-12 parts, Initiator: 0.05-2 parts, Reducing agent: 0.05-2 parts, Crosslinking agent: 1-10 parts, Minerals: 0-2 parts Water: 50-75 parts.

2. The paper surface strengthening agent according to claim 1, characterized in that: The polyvinyl alcohol is selected from at least one of 0588, 0599, 1788, 1792, 1799, 2088, 2099, 2488, and 2499; the cationic monomer is selected from at least one of methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, dimethyl diallyl ammonium chloride, acryloyl ethylenediamine hydrochloride, and N,N-dimethylaminopropyl ethyl methacrylate.

3. The paper surface strengthening agent according to claim 1, characterized in that: The anionic monomer is selected from at least one of itaconic acid, acrylic acid, and methacrylic acid; the acrylamide and the monomer containing active hydroxyl groups are selected from at least one of N-(hydroxymethyl)acrylamide, N-hydroxyethylacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and acrylamide.

4. The paper surface strengthening agent according to claim 1, characterized in that: The initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate; the reducing agent is selected from at least one of sodium sulfite, sodium bisulfite, sodium dithionite, and sodium metabisulfite.

5. The paper surface strengthening agent according to claim 1, characterized in that: The crosslinking agent is selected from at least one of modified silica, modified potassium zirconium carbonate, and modified ammonium zirconium carbonate; the mineral is selected from at least one of modified wollastonite and organobentonite.

6. A method for preparing a paper surface strengthening agent according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Add water and polyvinyl alcohol to the reaction apparatus, stir and heat to 80℃-95℃, and maintain for 0.5h-1.5h until completely dissolved; S2. At 80℃-95℃, add cationic monomers, anionic monomers, acrylamide and a mixture containing active hydroxyl monomers and vinylpyrrolidone dropwise, while simultaneously adding initiators and reducing agents. The dropwise addition time is 1h-5h, and the temperature is maintained for 0.5h-2h after the addition is complete. S3. Cool down to below 45℃, add crosslinking agent, react for 0.5h-1h to obtain the paper surface strengthening agent product; S4. Optionally, minerals are added during post-processing, stirred for 0.5-2 hours, filtered, and the paper surface strengthening agent is obtained.

7. The application of a paper surface strengthening agent as described in any one of claims 1-6 in papermaking.

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