A lignin rosin sizing agent, preparation method and application thereof

Abstract

The invention discloses a preparation method of a lignin rosin sizing agent, the method comprising the following steps: dissolving lignin and rosin in anhydrous ethanol, stirring and drying to obtain a lignin rosin sizing agent powder, that is, obtaining a lignin rosin sizing agent; wherein the mass ratio of rosin to lignin is 1:0.25-4. The method of the invention pioneered the exploration of the synergistic hydrophobic effect of green renewable lignin and rosin, and applied it to the field of liquid packaging paperboard. The method of the invention solves the problems of complex preparation process and low paper strength of the existing rosin sizing agent.

Description

Technical Field

[0001] The invention belongs to the technical field of rosin sizing agent processing, in particular to a lignin rosin sizing agent, a preparation method and application thereof. Background Art

[0002] Sizing agents can make paper or paperboard impermeable to ink, emulsion, and water, while improving the smoothness and other comprehensive properties of paper. Rosin is the most important and ideal in-slurry sizing agent in the papermaking process because it has low cost, good sizing effect, and high compatibility with pulp fibers and other sizing agents. In addition, my country is the world's largest rosin production base and has unique advantages in resources. Therefore, the research and development of rosin sizing agents is in line with my country's national conditions and has become an important research and development direction for papermaking sizing agents. The functional groups of rosin are mainly conjugated unsaturated double bonds and -COOH. In the rosin sizing process, the polar carboxyl group reacts with the hydrophilic paper surface to align the non-polar unsaturated double bonds and form a stable hydrophobic surface with reduced free energy.

[0003] However, due to the barrier effect of rosin between pulp fibers and the low retention rate of rosin, the physical strength of paper will be seriously reduced, thus affecting its application in actual production. Therefore, improving the strength performance of paper after sizing with rosin sizing agent is an urgent problem to be solved in the current sizing agent field.

[0004] Patent application No. 201310611305.1 discloses a new type of cationic rosin sizing agent, which has stable emulsion particle performance and significant sizing effect when used. However, it uses toxic chemicals such as styrene and epichlorohydrin, and the preparation process is not green and environmentally friendly. Patent application No. 201710694208.1 discloses an alkaline sizing agent in a cationic rosin emulsion, which can improve the gloss of paper, has good surface strength after sizing, and significantly improves dry and wet strength. However, its preparation process is complicated, and the performance of the emulsion sizing agent is not stable enough, and the storage time is short.

[0005] Therefore, it can be seen that the rosin sizing agent in the prior art cannot fully meet the needs of users, and therefore there is an urgent need for a rosin sizing agent that can ensure paper strength, has a simple and efficient preparation process, and can be stored for a long time. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a lignin rosin sizing agent, a preparation method and an application thereof.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A method for preparing a lignin rosin sizing agent, the method comprising the following steps:

[0009] The lignin and rosin are dissolved in anhydrous ethanol, stirred and dried to obtain a lignin rosin sizing agent powder, that is, the lignin rosin sizing agent is obtained;

[0010] Among them, the mass ratio of rosin to lignin is 1:0.25-4.

[0011] Furthermore, the mass ratio of rosin to lignin is 1:0.25, 1:0.5, 1:1, 1:2, or 1:4.

[0012] Furthermore, the stirring time is 10 to 60 minutes; and the drying temperature is 50 to 90°C.

[0013] Furthermore, the lignin is green and renewable lignin.

[0014] The lignin rosin sizing agent is prepared by the method as described above.

[0015] The application of the lignin rosin sizing agent as described above in the preparation of liquid packaging paperboard.

[0016] The method for making liquid packaging paperboard base paper using the above-mentioned lignin rosin sizing agent comprises the following steps:

[0017] (1) dispersing lignin rosin sizing agent powder in water to prepare lignin rosin sizing agent emulsion;

[0018] (2) Adding lignin rosin sizing agent emulsion into pulp to make liquid packaging paperboard base paper.

[0019] Furthermore, in the step (1), the mass concentration of the lignin rosin sizing agent emulsion is 5 to 50%.

[0020] Furthermore, in step (2), the basis weight of the liquid packaging paperboard is 80 to 200 g / m 2 .

[0021] The advantages and positive effects achieved by the present invention are:

[0022] 1. The method of the present invention pioneered the exploration of the synergistic hydrophobic effect of green renewable lignin and rosin, and applied it to the field of liquid packaging paperboard. The method of the present invention solves the problems of complex preparation process and low paper strength of the existing rosin sizing agent.

[0023] 2. The preparation process of the lignin rosin sizing agent of the present invention is simple, the reaction conditions are mild and controllable, it is easy to operate, suitable for large-scale production, and has broad application prospects.

[0024] 3. The present invention provides a stable and sustainable approach for the utilization of lignin. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a comparison diagram of the surface tension of the lignin rosin sizing agent emulsion at different rosin and lignin ratios in the present invention;

[0026] Figure 2 The figure is a comparison diagram of the particle sizes of the lignin rosin sizing agent emulsions at different rosin and lignin ratios in the present invention; wherein, figure a is a comparison diagram of the emulsion particle sizes, and figure b is the polydispersity index (PDI) of the emulsion particles;

[0027] Figure 3 This is a comparison diagram of the Zeta potential of the lignin rosin sizing agent emulsion at different rosin and lignin ratios in the present invention;

[0028] Figure 4 It is a comparison chart of the Cobb values ​​of Example 1 and Comparative Examples 1-5 in the present invention; wherein the left figure is a comparison chart of the Cobb values ​​of Example 1 and Comparative Examples 1-5, and the right figure is a comparison chart of the Cobb values ​​of Example 1 and Comparative Examples 2, 3, and 5;

[0029] Figure 5 It is a comparison diagram of the contact angles of Example 1 and Comparative Examples 1-5 in the present invention;

[0030] Figure 6 It is a comparison chart of the tensile index of Example 1 and Comparative Examples 1-5 in the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the embodiments. The following embodiments are descriptive rather than restrictive, and the protection scope of the present invention cannot be limited by the following embodiments.

[0032] The various experimental operations involved in the specific embodiments are all routine techniques in the art. For parts not specially annotated in this document, ordinary technicians in the art can implement them by referring to various commonly used reference books, scientific and technological literature or related instructions, manuals, etc. before the filing date of this invention.

[0033] A method for preparing a lignin rosin sizing agent, the method comprising the following steps:

[0034] The lignin and rosin are dissolved in anhydrous ethanol, stirred and dried to obtain a lignin rosin sizing agent powder, that is, the lignin rosin sizing agent is obtained;

[0035] Among them, the mass ratio of rosin to lignin is 1:0.25-4.

[0036] Preferably, the mass ratio of rosin to lignin is 1:0.25, 1:0.5, 1:1, 1:2, or 1:4.

[0037] Preferably, the stirring time is 10 to 60 minutes and the drying temperature is 50 to 90°C.

[0038] Preferably, the lignin is green renewable lignin.

[0039] The lignin rosin sizing agent is prepared by the method as described above.

[0040] The application of the lignin rosin sizing agent as described above in the preparation of liquid packaging paperboard.

[0041] The method for making liquid packaging paperboard base paper using the above-mentioned lignin rosin sizing agent comprises the following steps:

[0042] (1) dispersing lignin rosin sizing agent powder in water to prepare lignin rosin sizing agent emulsion;

[0043] (2) Adding lignin rosin sizing agent emulsion into pulp to make liquid packaging paperboard base paper.

[0044] Preferably, in step (1), the mass concentration of the lignin rosin sizing agent emulsion is 5 to 50%.

[0045] Preferably, in step (2), the basis weight of the liquid packaging paperboard is 80 to 200 g / m 2 .

[0046] Specifically, the relevant preparation and detection are as follows:

[0047] The lignin in the present invention can be purchased from Shanghai McLean Biochemical Technology Co., Ltd., with the item number L849279; the rosin in the present invention can be purchased from Shanghai McLean Biochemical Technology Co., Ltd., with the item number C832364. The aluminum sulfate in the present invention can be purchased from Shanghai McLean Biochemical Technology Co., Ltd., with the item number A801783.

[0048] Example 1

[0049] A method for preparing a lignin rosin sizing agent, the method comprising the following steps:

[0050] Preparation of lignin rosin sizing agent powder:

[0051] 10 g of rosin and 20 g of lignin were placed in 20 ml of anhydrous ethanol and mixed thoroughly. The solution was then magnetically stirred for 30 minutes. After the stirring, the anhydrous ethanol was recovered by rotary evaporation and the residue was placed in an oven at 50°C and dried for 12 hours to obtain a lignin rosin sizing agent powder.

[0052] The method for making base paper of liquid packaging paperboard by using the above-mentioned lignin rosin sizing agent comprises the following steps:

[0053] (1) Preparation of lignin rosin sizing agent emulsion:

[0054] 1 g of lignin rosin sizing agent powder was dispersed in 10 g of deionized water, and ultrasonically dispersed for 30 minutes to prepare a lignin rosin sizing agent emulsion with a concentration of 10%.

[0055] (2) Production of liquid packaging paperboard:

[0056] Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5, then add lignin rosin sizing agent emulsion, and make sheets on a fast paper former. The basis weight of liquid packaging paperboard is 160g / m 2 .

[0057] Example 2

[0058] A method for preparing a lignin rosin sizing agent, the method comprising the following steps:

[0059] Preparation of lignin rosin sizing agent powder:

[0060] 10 g of rosin and 5 g of lignin were placed in 20 ml of anhydrous ethanol and mixed thoroughly. The solution was then magnetically stirred for 30 minutes. After the stirring, the anhydrous ethanol was recovered by rotary evaporation, and the residue was placed in an oven at 50°C and dried for 12 hours to obtain a lignin rosin sizing agent powder.

[0061] The method for making base paper of liquid packaging paperboard by using the above-mentioned lignin rosin sizing agent comprises the following steps:

[0062] (1) Preparation of lignin rosin sizing agent emulsion:

[0063] 1 g of lignin rosin sizing agent powder was dispersed in 10 g of deionized water, and ultrasonically dispersed for 30 minutes to prepare a lignin rosin sizing agent emulsion with a concentration of 10%.

[0064] (2) Production of liquid packaging paperboard:

[0065] Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5, then add lignin rosin sizing agent emulsion, and make sheets on a fast paper former. The basis weight of liquid packaging paperboard is 160g / m 2 .

[0066] Example 3

[0067] A method for preparing a lignin rosin sizing agent, the method comprising the following steps:

[0068] Preparation of lignin rosin sizing agent powder:

[0069] 10 g of rosin and 10 g of lignin were placed in 20 ml of anhydrous ethanol and mixed thoroughly. The solution was then magnetically stirred for 30 minutes. After the stirring, the anhydrous ethanol was recovered by rotary evaporation, and the residue was placed in an oven at 50°C and dried for 12 hours to obtain a lignin rosin sizing agent powder.

[0070] The method for making base paper of liquid packaging paperboard by using the above-mentioned lignin rosin sizing agent comprises the following steps:

[0071] (1) Preparation of lignin rosin sizing agent emulsion:

[0072] 1 g of lignin rosin sizing agent powder was dispersed in 10 g of deionized water, and ultrasonically dispersed for 30 minutes to prepare a lignin rosin sizing agent emulsion with a concentration of 10%.

[0073] (2) Production of liquid packaging paperboard:

[0074] Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5, then add lignin rosin sizing agent emulsion, and make sheets on a fast paper former. The basis weight of liquid packaging paperboard is 160g / m 2 .

[0075] Example 4

[0076] A method for preparing a lignin rosin sizing agent, the method comprising the following steps:

[0077] Preparation of lignin rosin sizing agent powder:

[0078] 10 g of rosin and 40 g of lignin were placed in 20 ml of anhydrous ethanol and mixed thoroughly. The solution was then magnetically stirred for 30 minutes. After the stirring, the anhydrous ethanol was recovered by rotary evaporation, and the residue was placed in an oven at 50°C and dried for 12 hours to obtain a lignin rosin sizing agent powder.

[0079] The method for making base paper of liquid packaging paperboard by using the above-mentioned lignin rosin sizing agent comprises the following steps:

[0080] (1) Preparation of lignin rosin sizing agent emulsion:

[0081] 1 g of lignin rosin sizing agent powder was dispersed in 10 g of deionized water, and ultrasonically dispersed for 30 minutes to prepare a lignin rosin sizing agent emulsion with a concentration of 10%.

[0082] (2) Production of liquid packaging paperboard:

[0083] Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5, then add lignin rosin sizing agent emulsion, and make sheets on a fast paper former. The basis weight of liquid packaging paperboard is 160g / m 2 .

[0084] Figure 1 The surface tension comparison chart of lignin rosin sizing agent emulsion at different rosin and lignin ratios is shown in the figure. The detection method is: using a surface tension meter, the static surface tension of lignin rosin sizing agent emulsion at different rosin and lignin ratios is measured by the hanging plate method in a constant temperature water bath at 25°C, and each sample is measured 3 times.

[0085] Figure 2 The figure is a comparison of the particle size and polydispersity index (PDI) of lignin rosin sizing agent emulsion at different rosin and lignin ratios. The detection method is: the solution concentration of different rosin and lignin ratios is prepared to be 5 mg / mL, an appropriate amount of sample is added to the sample pool, and the Malvern particle size analyzer is used to measure at room temperature 25°C, and the number of measurements is set to three times.

[0086] Figure 3 This is a comparison chart of the Zeta potential of lignin rosin sizing agent emulsions at different rosin and lignin ratios. The detection method is: prepare solutions with different rosin and lignin ratios at a concentration of 5 mg / mL, take an appropriate amount of sample and add it to the sample pool, use a Malvern particle size analyzer to measure at room temperature 25°C, and set the measurement number to three times.

[0087] like Figure 1 It can be seen that the surface tension gradually decreases with the increase of the proportion of lignin in the lignin rosin sizing agent emulsion and then tends to be stable. When the mass ratio of rosin to lignin is 1:2, the interaction between molecules (electrostatic repulsion) causes the diffusion of lignin to the surface to gradually decrease, and then the surface tension tends to be stable. Figure 2 The particle size and PDI changes of the emulsion are shown in Figure 2. When the mass ratio of rosin to lignin is 1:2, the PDI value is the lowest, indicating that the emulsion has the best stability. In addition, the Zeta potential of the lignin rosin sizing agent emulsion at different rosin to lignin ratios was also tested. The results are shown in Figure 2. Figure 3 As shown. Zeta potential is a measure of the strength of mutual repulsion or attraction between particles. The smaller the molecule or dispersed particle, the higher the absolute value of the Zeta potential and the more stable the system, that is, the dissolution or dispersion can resist aggregation. From the analysis of the lignin structure, the hydroxyl and carboxyl groups in the hydrophilic part make the Zeta potential of the emulsion negative. When the mass ratio of rosin to lignin is 1:2, the absolute value of the Zeta potential of the emulsion is greater than 60mV, the particles tend to repel each other, and it is not easy to aggregate, and the emulsion stability is excellent.

[0088] Comparative Example 1

[0089] Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5, and then make sheets on a fast paper former. The basis weight of the liquid packaging paperboard base paper is 160g / m 2 .

[0090] Comparative Example 2

[0091] A rosin size in a novel cationic rosin sizing agent disclosed in patent application No. 201310611305.1 was selected as comparative example 2, and the pulp papermaking experiment and the hydrophobicity detection experiment were carried out with the same quantitative amount. The remaining papermaking steps were the same as those in Example 1.

[0092] Comparative Example 3

[0093] A rosin size in an alkaline sizing agent in a cationic rosin emulsion disclosed in patent application number 201710694208.1 was selected as comparative example 3, and the pulp papermaking experiment and the hydrophobicity detection experiment were carried out with the same quantitative amount. The remaining papermaking steps were the same as in Example 1.

[0094] Comparative Example 4

[0095] The method for making base paper of liquid packaging paperboard by using a sizing agent comprises the following steps:

[0096] (1) Preparation of sizing agent: 10 g of lignin was added to 20 ml of anhydrous ethanol and mixed thoroughly. The solution was then magnetically stirred for 30 minutes to allow the lignin to be fully dispersed in the anhydrous ethanol solution to obtain a lignin dispersion.

[0097] (2) Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5. Then add lignin dispersion liquid and make sheets on a fast paper former. The basis weight of the liquid packaging paperboard base paper is 160g / m 2 .

[0098] Comparative Example 5

[0099] The method for making base paper of liquid packaging paperboard by using a sizing agent comprises the following steps:

[0100] (1) Preparation of sizing agent: 10 g of rosin was added to 20 ml of anhydrous ethanol and mixed thoroughly. The solution was then magnetically stirred for 30 minutes to allow the rosin to be fully dissolved in the anhydrous ethanol solution to obtain a rosin solution.

[0101] (2) Select softwood with a beating degree of 30°SR and mix it with mechanical pulp at a mass ratio of 1:2. Use aluminum sulfate to adjust the pulp pH to 5.5. Then add rosin solution and make sheets on a fast paper former. The basis weight of the liquid packaging paperboard base paper is 160g / m 2 .

[0102] The Cobb value of the lignin rosin sizing agent prepared in Example 1 was compared, and the test results were as follows: Figure 4 The test method is as follows: the Cobb value of paper is measured according to the standard GB / T1540-2002 using a 61-67 type automatic Cobb value tester (TMI, USA).

[0103] The contact angle of the lignin rosin sizing agent prepared in Example 1 was compared, and the test results were as follows: Figure 5 The test method is as follows: The contact angle is measured according to the standard ISO / TS14778:2021 using a PGX dynamic contact angle meter (FIBRO, Sweden).

[0104] The tensile index of the lignin rosin sizing agent prepared in Example 1 was compared, and the test results were as follows: Figure 6 The test method is as follows: the tensile index is measured and calculated according to QB / T1053-2004 using a 066 type tensile strength instrument (L&W, Sweden).

[0105] The hydrophobicity test results are as follows Figure 4 and Figure 5 As shown. Compared with the lignin rosin sizing agent prepared in Example 1, Comparative Example 1 has no hydrophobic effect. The hydrophobicity of the sizing agents prepared in Comparative Examples 2 and 3 is lower than that in Example 1. In Comparative Example 4, only lignin is added without hydrophobic effect. Although only rosin is added in Comparative Example 5, there is a good hydrophobic effect, but its preparation process requires the use of solvent dissolution, and the solvent cannot be recovered, which is not environmentally friendly to a certain extent.

[0106] Strength performance test results are as follows Figure 6 As shown, the paper strength of the sizing agents prepared in Comparative Examples 1 to 3 is lower than that of Example 1. In Comparative Example 4, only adding lignin can significantly improve the strength of the paper. In Comparative Example 5, only adding rosin can significantly reduce the strength of the paper.

[0107] Therefore, it can be seen that there is a synergistic effect between lignin and rosin in the lignin rosin sizing agent prepared by the method of the present invention, which can effectively improve the hydrophobicity and strength properties of the finished paper.

[0108] In summary, the present invention discloses a method for preparing a lignin rosin sizing agent. The prepared sizing agent not only has excellent hydrophobicity, but also can improve the strength performance of paper. The preparation process is green and efficient, and can be applied to liquid packaging paperboard.

[0109] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing a lignin rosin sizing agent, characterized in that: The method comprises the following steps: Preparation of lignin rosin sizing agent powder: 10 g of rosin and 20 g of lignin were put into 20 mL of anhydrous ethanol and mixed thoroughly, and then the solution was magnetically stirred for 30 minutes. After the end, the anhydrous ethanol was recovered by rotary evaporation, and the residue was placed in a 50°C oven and dried for 12 hours to obtain a lignin rosin sizing agent powder; When the mass ratio of rosin to lignin is 1:2, the absolute value of the emulsion Zeta potential is greater than 60 mV, the particles tend to repel each other, and the emulsion stability is excellent.

2. The lignin rosin sizing agent prepared according to the method of claim 1.

3. Use of the lignin rosin sizing agent as claimed in claim 2 in the preparation of liquid packaging paperboard.

4. A method for making liquid packaging paperboard base paper using the lignin rosin sizing agent as claimed in claim 2, characterized in that: The steps include: (1) dispersing lignin rosin sizing agent powder in water to prepare lignin rosin sizing agent emulsion; (2) Adding lignin rosin sizing agent emulsion into pulp to make liquid packaging paperboard base paper.

5. The method according to claim 4, characterized in that: In the step (1), the mass concentration of the lignin rosin sizing agent emulsion is 5 to 50%.

6. The method according to claim 4 or 5, characterized in that: In the step (2), the basis weight of the liquid packaging paperboard is 80 to 200 g / m 2 .

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