A kind of AKD surface sizing agent and preparation method thereof

Abstract

The invention relates to the technical field of sizing agents, and proposes an AKD surface sizing agent and a preparation method thereof. An AKD surface sizing agent comprises the following component raw materials in parts by weight: 10-20 parts of AKD wax powder, 2-4 parts of emulsifier, 70-80 parts of water, and 0.3-0.5 parts of stabilizer; the emulsifier comprises cationic starch. Through the above technical scheme, the problems of low water resistance and low mechanical strength of the surface sizing agent in the related art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of sizing agents, and in particular to an AKD surface sizing agent and a preparation method thereof. Background Art

[0002] AKD surface sizing agent is an important chemical widely used in the papermaking field. It mainly forms a waterproof film on the surface of paper, thus giving the paper good water resistance and reducing the absorption and penetration of liquids by the paper. This is of key significance for improving the printing adaptability, writing performance and moisture resistance of the paper. In the production process of many paper products such as cultural paper and packaging paper, AKD surface sizing agent plays an indispensable role.

[0003] However, with the continuous development of the papermaking industry and the increasing requirements for paper quality, traditional AKD surface sizing agents have gradually exposed some problems in practical applications. For example, in some high-humidity environments or long-term contact with liquids, its water resistance is still difficult to fully meet the needs, which may lead to problems such as paper strength reduction, deformation, and even damage. In terms of mechanical strength, when AKD surface sizing agents are used in packaging materials, printing paper and other products, the products need to have certain mechanical strength. Therefore, it is necessary to develop an AKD surface sizing agent with high water resistance and high mechanical strength. Summary of the invention

[0004] The invention provides an AKD surface sizing agent and a preparation method thereof, which solves the problems of low water resistance and low mechanical strength of the surface sizing agent in the related art.

[0005] The technical scheme of the present invention is as follows: The present invention proposes an AKD surface sizing agent, comprising the following component raw materials in parts by weight: 10-20 parts of AKD wax powder, 2-4 parts of emulsifier, 70-80 parts of water, and 0.3-0.5 parts of stabilizer; the emulsifier comprises cationic starch.

[0006] As a further technical solution, the emulsifier further includes a hydroxyalkaneamide compound, and the mass ratio of the cationic starch to the hydroxyalkaneamide compound is 2-3:1.

[0007] In the present invention, hydroxyalkaneamide compounds and cationic starch are added as emulsifiers at the same time to exert the synergistic effect of the two, promote the formation of a denser and continuous water transport layer, strengthen the fiber network structure, and further enhance the water resistance and mechanical strength of the paper.

[0008] As a further technical solution, the hydroxyalkaneamide compound includes one or more of N,N-di(2-hydroxyethyl)-hexadecaneamide, N,N-diethanol dodecaneamide, and N-(1,3-dihydroxy-2-octadecyl)butanamide.

[0009] As a further technical solution, the hydroxyalkaneamide compound is preferably N,N-bis(2-hydroxyethyl)-hexadecaneamide.

[0010] As a further technical solution, the stabilizer includes one or both of polyvinyl alcohol and polyethylene glycol.

[0011] As a further technical solution, the raw material also includes 3 to 5 parts of polyvinyl butyral.

[0012] In the present invention, polyvinyl butyral is added and mixed with AKD wax powder to exert the synergistic effect of the two, further promote the formation of the water transport layer, enhance the interaction between the sizing agent and the paper fiber, and further improve the water resistance and mechanical strength of the paper.

[0013] As a further technical solution, the polyvinyl butyral consists of a first polyvinyl butyral and a second polyvinyl butyral, and the first polyvinyl butyral and the second polyvinyl butyral have different butyraldehyde group contents.

[0014] As a further technical solution, the butyraldehyde content of the first polyvinyl butyral is 43wt%~50wt%, the butyraldehyde content of the second polyvinyl butyral is 70wt%~75wt%, and the mass ratio of the first polyvinyl butyral to the second polyvinyl butyral is 1~2:1.

[0015] In the present invention, a first polyvinyl butyral with different butyraldehyde content is added and mixed with a second polyvinyl butyral to exert a synergistic effect, promote the sizing agent to produce an effective water transport layer at different time stages, exert a better filling and bonding effect in the sizing agent, and further improve the water resistance and mechanical strength of the paper.

[0016] The present invention also provides a method for preparing an AKD surface sizing agent, comprising the following steps: S1, mixing the emulsifier and water uniformly to obtain an emulsifier solution; S2, after melting the AKD wax powder, adding the emulsifier solution, shearing, homogenizing, cooling, and sieving to obtain a mixture; S3. Add stabilizer to the mixture and mix evenly to obtain AKD surface sizing agent.

[0017] As a further technical solution, the mixing temperature in S1 is 70-80°C.

[0018] As a further technical solution, the temperature of the emulsifier solution in S2 is 70-80°C.

[0019] As a further technical solution, the melting temperature in S2 is 70-80°C.

[0020] As a further technical solution, the shearing temperature in S2 is 70-80°C, the shearing time is 20-30min, and the shearing speed is 2000-3000r / min.

[0021] As a further technical solution, the homogenization pressure in S2 is 20~30MPa.

[0022] As a further technical solution, the diameter of the sieve is 200 meshes.

[0023] The working principle and beneficial effects of the present invention are: In the present invention, AKD wax powder is used as a raw material, and cationic starch is added as an emulsifier to prepare an AKD surface sizing agent. Cationic starch as an emulsifier can effectively enhance the dispersibility and stability of AKD wax powder in the system, so that the AKD wax powder is more evenly distributed in the surface sizing process of paper, promotes the AKD wax powder to better combine with paper fibers and form a hydrophobic layer, significantly reduces the water absorption of paper, and improves the water resistance and mechanical strength of paper. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the following examples and comparative examples: AKD wax powder: AKD content is 91.02wt%, the manufacturer is Shandong Dingke New Materials Co., Ltd.; Cationic starch: cationic starch content 99wt%, manufacturer is Dezhou Runde Starch Co., Ltd.; Polyvinyl alcohol: model 2488; Polyethylene glycol: model PEG400; The first polyvinyl butyral has a butyraldehyde content of 43 wt% to 50 wt%, purchased from MacLean Reagent; The second polyvinyl butyral: the butyraldehyde content is 70wt%~75wt%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0026] Example 1 A method for preparing an AKD surface sizing agent comprises the following steps: S1, mixing 2 parts of cationic starch with 70 parts of water at 70° C. to obtain an emulsifier solution; S2, heating 10 parts of AKD wax powder to 70°C to melt, adding emulsifier solution, keeping at 70°C, shearing at 2000r / min for 30min, passing through a homogenizer at a pressure of 20MPa, cooling, and passing through a 200-mesh sieve to obtain a mixture; S3. Add 0.3 parts of polyvinyl alcohol to the mixture and mix well to obtain AKD surface sizing agent.

[0027] Example 2 A method for preparing an AKD surface sizing agent comprises the following steps: S1, mix 3 parts of cationic starch and 75 parts of water at 75° C. to obtain an emulsifier solution; S2, heating 15 parts of AKD wax powder to 75°C to melt, adding emulsifier solution, keeping at 75°C, shearing at 2500r / min for 25min, passing through a homogenizer at a pressure of 25MPa, cooling, and passing through a 200-mesh sieve to obtain a mixture; S3. Add 0.4 parts of polyvinyl alcohol to the mixture and mix evenly to obtain AKD surface sizing agent.

[0028] Example 3 A method for preparing an AKD surface sizing agent comprises the following steps: S1, mixing 4 parts of cationic starch and 80 parts of water at 80° C. to obtain an emulsifier solution; S2, heating 20 parts of AKD wax powder to 80°C to melt, adding emulsifier solution, keeping the temperature at 80°C, shearing at 3000r / min for 20min, passing through a homogenizer at a pressure of 30MPa, cooling, and passing through a 200-mesh sieve to obtain a mixture; S3. Add 0.5 parts of polyethylene glycol to the mixture and mix evenly to obtain AKD surface sizing agent.

[0029] Example 4 Compared with Example 1, the difference of Example 4 is that the cationic starch is replaced by an equal amount of N,N-diethanol dodecylamide.

[0030] Example 5 Compared with Example 1, the difference of Example 5 is that the cationic starch is replaced with a 2:1 composition of cationic starch and N,N-diethanol dodecylamide.

[0031] Example 6 Compared with Example 1, the difference of Example 6 is that the cationic starch is replaced with a 3:1 composition of cationic starch and N,N-diethanol dodecylamide.

[0032] Example 7 Compared with Example 6, Example 7 is different in that N,N-diethanol dodecanoic acid amide is replaced by an equal amount of N,N-di(2-hydroxyethyl)-hexadecanoic acid amide.

[0033] Example 8 Compared with Example 6, Example 8 is different in that N,N-diethanol dodecylamide is replaced by an equal amount of N-(1,3-dihydroxy-2-octadecyl)butyramide.

[0034] Example 9 Compared with Example 7, the difference of Example 9 lies in step S2. Step S2 of this embodiment is: after heating 10 parts of AKD wax powder to 70°C and melting, add emulsifier solution and 3 parts of polyvinyl butyral, keep warm at 60°C, shear at 2000r / min for 30min, pass through a homogenizer at a pressure of 20Mpa, cool, and crush through a 200-mesh sieve to obtain a mixture; wherein the polyvinyl butyral is the first polyvinyl butyral.

[0035] Example 10 Compared with Example 9, the difference in Example 10 is that the added amount of the first polyvinyl butyral is 5 parts.

[0036] Embodiment 11 Compared with Example 10, Example 11 is different in that the first polyvinyl butyral is replaced by an equal amount of the second polyvinyl butyral.

[0037] Example 12 Compared with Example 10, Example 12 is different in that 5 parts of the first polyvinyl butyral are replaced by the first polyvinyl butyral and the second polyvinyl butyral in a mass ratio of 1:1.

[0038] Example 13 Compared with Example 10, Example 13 is different in that 5 parts of the first polyvinyl butyral are replaced by the first polyvinyl butyral and the second polyvinyl butyral in a mass ratio of 2:1.

[0039] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that the cationic starch is replaced by an equal amount of sodium lauryl sulfate.

[0040] The AKD surface sizing agents prepared in Examples 1 to 13 and Comparative Example 1 were mixed with water to prepare an AKD surface sizing agent emulsion with a solid content of 30% for sizing application.

[0041] Sizing process: Stir the oxidized starch (mass concentration of 10%) and heat it to 90℃. Keep it warm for 30min and then adjust it to 65℃. Add AKD surface sizing agent emulsion. The added amount is: the mass ratio of oxidized starch to AKD surface sizing agent emulsion is 20:4. Use electrostatic copy paper as the sizing base paper. Use the above sizing material on a small sizing machine in the laboratory with the same sizing amount (1.7g / m 2 ) were sizing on one side, and the sizing paper samples were dried in an oven at the same temperature and time (140℃×120s). After aging for 5 minutes, the sizing paper samples were prepared. The sizing paper samples were tested according to the following method: 1. Water absorption value: According to the test method specified in GB / T 1540-2002 "Water absorption of paper and paperboard - Water absorption method", the water absorption value of the test sample is tested for 60s.

[0042] 2. Tensile strength: Test the tensile strength of the sample according to the test method specified in GB / T 12914-2018 "Determination of tensile strength of paper and paperboard - Constant rate tensile method (20 mm / min)".

[0043] The test results are shown in the following table: Table 1 Performance test results of AKD surface sizing agents prepared in Examples 1 to 13 and Comparative Example 1

[0044] Compared with Comparative Example 1, Example 1 adds cationic starch as an emulsifier. As a result, the caloric value of Example 1 is smaller than that of Comparative Example 1, and the tensile strength is better than that of Example 1, indicating that when cationic starch is added as an emulsifier, the water resistance and mechanical strength of paper can be improved.

[0045] Compared with Examples 1 and 4, Examples 5 to 8 simultaneously added cationic starch and hydroxyalkaneamide compounds as emulsifiers. As a result, the cobalt values ​​of Examples 5 to 8 were smaller than those of Examples 1 and 4, and the tensile strength was better than that of Examples 1 and 4, indicating that cationic starch and hydroxyalkaneamide compounds exerted a synergistic effect, which could further improve the water resistance and mechanical strength of paper.

[0046] In Examples 6 and 7, different types of hydroxyalkaneamide compounds were added. As a result, the Ke Bo value of Example 7 was smaller than that of Examples 6 and 8, and the tensile strength was better than that of Examples 6 and 8, indicating that when the added hydroxyalkaneamide compound was N,N-di(2-hydroxyethyl)-hexadecanoic acid amide, the water resistance and mechanical strength of the paper could be further improved.

[0047] Compared with Example 7, Examples 9 to 11 added polyvinyl butyral. As a result, the Kebo values ​​of Examples 9 to 11 were smaller than those of Example 7, and the tensile strength was better than that of Example 7, indicating that the addition of polyvinyl butyral can further enhance the water resistance and mechanical strength of paper.

[0048] Compared with Examples 9 to 11, Examples 12 and 13 simultaneously add the first polyvinyl butyral and the second polyvinyl butyral. As a result, the Kebo values ​​of Examples 12 and 13 are smaller than those of Examples 9 to 11, and the tensile strength is better than that of Examples 9 to 11, indicating that the first polyvinyl butyral and the second polyvinyl butyral play a synergistic role and can further improve the water resistance and mechanical strength of the paper.

[0049] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An AKD surface sizing agent, characterized in that: The invention comprises the following raw materials in parts by weight: 10-20 parts of AKD wax powder, 2-4 parts of emulsifier, 70-80 parts of water and 0.3-0.5 parts of stabilizer; the emulsifier comprises cationic starch.

2. An AKD surface sizing agent according to claim 1, characterized in that: The emulsifier further comprises a hydroxyalkaneamide compound, and the mass ratio of the cationic starch to the hydroxyalkaneamide compound is 2-3:

1.

3. An AKD surface sizing agent according to claim 2, characterized in that: The hydroxyalkaneamide compound includes one or more of N,N-di(2-hydroxyethyl)-hexadecaneamide, N,N-diethanol dodecaneamide, and N-(1,3-dihydroxy-2-octadecyl)butanamide.

4. An AKD surface sizing agent according to claim 1, characterized in that: The stabilizer includes one or both of polyvinyl alcohol and polyethylene glycol.

5. An AKD surface sizing agent according to claim 1, characterized in that: The raw materials also include 3 to 5 parts of polyvinyl butyral.

6. An AKD surface sizing agent according to claim 5, characterized in that: The polyvinyl butyral consists of a first polyvinyl butyral and a second polyvinyl butyral, and the first polyvinyl butyral and the second polyvinyl butyral have different butyraldehyde group contents.

7. An AKD surface sizing agent according to claim 6, characterized in that: The butyraldehyde content of the first polyvinyl butyral is 43wt%-50wt%, the butyraldehyde content of the second polyvinyl butyral is 70wt%-75wt%, and the mass ratio of the first polyvinyl butyral to the second polyvinyl butyral is 1-2:

1.

8. The method for preparing an AKD surface sizing agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, mixing the emulsifier and water uniformly to obtain an emulsifier solution; S2, after melting the AKD wax powder, adding the emulsifier solution, shearing, homogenizing, cooling, and sieving to obtain a mixture; S3. Add stabilizer to the mixture and mix evenly to obtain AKD surface sizing agent.

9. The method for preparing an AKD surface sizing agent according to claim 8, characterized in that: The melting temperature is 70-80°C.

10. The method for preparing an AKD surface sizing agent according to claim 8, characterized in that: The shearing temperature is 60-70° C., the shearing time is 20-30 min, and the shearing speed is 2000-3000 r / min.

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