Quick-drying cylinder adhesive and preparation method thereof

Abstract

The preparation method comprises the following steps: S1, adding diethylenetriamine into a four-neck flask, adding adipic acid in a stirring state, controlling the temperature to be 150-180 DEG C, carrying out heat preservation for 3-5 hours, after the reaction is finished, adding purified water to adjust the solid content to be 30%-55%, adjusting the pH value, and collecting the material for later use; s2, heating purified water, starting stirring, adding a polyvinyl alcohol solid in batches, stirring and dissolving, cooling to room temperature, and adjusting pH to obtain a polyvinyl alcohol solution; and S3, adding the polyamide polyamine intermediate solution into a four-neck flask, heating to 70-80 DEG C, slowly adding a polyvinyl alcohol solution while stirring, fully reacting, adjusting the pH value, adding purified water to adjust the solid content to 12-15%, and adding a bactericide, thereby obtaining the polyamide polyamine composite material. The cylinder adhesive has the advantages that after the cylinder adhesive is used, the contact time of paper sheets on a drying cylinder is short, the drying is fast, the film forming effect is good, and the dryness and humidity of the paper sheets are uniform.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking papermaking adhesives, in particular to a quick-drying papermaking adhesive and a preparation method thereof. Background Art

[0002] A widely used water-soluble adhesive for paper drying is polyamide-polyamine-epichlorohydrin resin, or PAE resin. It is a thermosetting resin with a polyamide-polyamine backbone and epichlorohydrin as a crosslinker. PAE resin inherently offers excellent flexibility and water solubility. It has low viscosity and easy leveling in water, resulting in uniformity. One epichlorohydrin molecule can link to two to three polyamide-polyamine molecules, increasing the molecular weight and number of end groups, resulting in stronger adhesion. However, this type of adhesive forms a hard, water-resistant coating film on the drying cylinder, severely impacting paper drying efficiency and dryness / wetness uniformity. It also significantly affects coating uniformity and softness, while also resulting in high steam energy consumption. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a fast-drying cylinder adhesive and a preparation method thereof, aiming to overcome the above-mentioned shortcomings of the existing PAE resin cylinder adhesive to at least a certain extent.

[0004] The present invention solves the above technical problems with the following technical solutions: A method for preparing a fast-drying cylinder adhesive comprises the following steps:

[0005] S1. Preparation of polyamide-polyamine intermediate solution: Add diethylenetriamine to a four-necked flask. Slowly add adipic acid to the reaction system while stirring. Maintain the temperature at 150-180°C for 3-5 hours. Collect the evaporated water and weigh it. After the reaction is complete, add purified water to adjust the solids content of the polyamide-polyamine intermediate to 30%-55%, adjust the pH to 8-10, and store the solution for later use.

[0006] S2. Preparation of polyethylene solution: Heat purified water to 60-70°C with stirring. Add polyvinyl alcohol solid in batches and stir for 0.5-4 hours until the solid is completely dissolved. Cool to room temperature and adjust the pH to 8-10 with a pH adjuster to obtain a polyvinyl alcohol solution.

[0007] S3. Preparation of cylinder adhesive: Add the polyamide polyamine intermediate solution to a four-necked flask, raise the temperature to 70-80°C, slowly add the polyvinyl alcohol solution while stirring, and after sufficient reaction, adjust the pH of the reaction solution to 6.5-10, add purified water to adjust the solid content to 12%-15%, and add a fungicide to obtain the cylinder adhesive.

[0008] On the basis of the above technical solutions, the present invention may further have the following specific options or more preferred options.

[0009] Specifically, in step S1, the molar ratio of diethylenetriamine to adipic acid is 1:1.0-1.1, and the reaction time is 3-10 h.

[0010] Specifically, the polyvinyl alcohol solid in step S2 is any one of type 5-88 and type 17-88, or a mixture of the two.

[0011] Specifically, the concentration of the polyvinyl alcohol solution obtained in step S2 is 5% to 15%.

[0012] Preferably, in step S3, the mass ratio of polyvinyl alcohol to polyamide polyamine intermediate is 0.2-0.35:1.

[0013] Specifically, after the polyvinyl alcohol solution is added in step S3, the mixture is stirred and reacted for 1 to 5 hours.

[0014] Specifically, the fungicide added in step S3 is either one of isothiazolinone and benzisothiazolinone or a mixture of the two.

[0015] Specifically, the content of the fungicide in the anti-tank agent is 100-500 ppm.

[0016] Specifically, the pH regulator used in steps S1 and S2 is a mixture of any one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

[0017] The present invention also provides a fast-drying cylinder adhesive, which is prepared by the above-mentioned preparation method.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The adhesive provided by the present invention can be used on high-speed paper machines. Using this adhesive shortens the contact time of paper sheets on the dryer, dries quickly, forms a good film, and achieves uniform dryness and wetness. The adhesive exhibits excellent adhesion across a wide range of dryness and wetness, improves dryer coating uniformity, provides excellent dryer protection, and effectively reduces Yankee wear. Furthermore, it exhibits excellent low-temperature film-forming properties, meeting the operational requirements of high-speed paper machines and appropriately lowering dryer temperatures, thereby reducing steam consumption in paper mills. DETAILED DESCRIPTION

[0020] The technical solutions provided by the present invention are described clearly and completely below with reference to specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0021] To avoid redundancy, the raw materials used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods in the art unless otherwise specified.

[0022] Example 1

[0023] Preparation of polyamide polyamine intermediate solution:

[0024] Add 304.18 g of diethylenetriamine to a 5 L four-necked flask equipped with a distillation condenser, thermometer, and stirrer. Turn on the stirring mechanism and raise the temperature to 100°C. Slowly add 602.28 g of adipic acid in portions while stirring. The system exotherms. After the addition is complete, raise the temperature to 165°C and maintain the reaction for 3 hours before removing the heater. Allow the temperature to cool below 120°C before adding 1552.94 g of 80°C hot water dropwise. Stir evenly, cool to room temperature, and adjust the pH to 8-10. The resulting bright yellow liquid is the polyamide-polyamine intermediate solution (PA solution) with a solids content of 34%.

[0025] Example 2

[0026] Preparation of polyvinyl alcohol solution:

[0027] Heat purified water to 65°C, weigh 90 g of the heated purified water, add it to the reaction flask, start stirring, add a total of 10.0 g of polyvinyl alcohol 17-88 solid in two batches, stir and react for 2 h until all the solids are dissolved, cool to room temperature, and adjust the pH to 8-10 with a pH regulator to obtain a polyvinyl alcohol solution (PVA solution) with a solid content of 10%. Collect the material for later use.

[0028] Example 3

[0029] First, add 89.18 g of PA solution (solid content 34%) to the reaction bottle, start stirring, raise the temperature to 75 ° C, slowly add 60.82 g of PVA17-88 solution (content 10.0%), and stir at 75 ° C for 1 h; adjust the pH to 8.9-9.1, add 153.75 g of water to adjust the solid content of the product to 12%-14%, add 0.05 g of isothiazolinone, stir evenly, and collect the material to obtain the cylinder adhesive product.

[0030] Example 4

[0031] The reactor was cleaned, 2.34 kg of purified water was added, stirring was started, and 0.26 kg of PVA 5-88 solid was added, stirred for 10 min, heating was started, the temperature was raised to 70 ° C, and stirring was performed for 1 h; the temperature was cooled to room temperature, and the pH was adjusted to 9.0-9.5 with 20% NaOH to obtain a PVA solution with a solid content of 10% for standby use; 3.58 kg of PA solution (solid content 34%) was added to the reactor, stirring was started, the temperature was raised to 70 ° C, and 2.42 kg of the above-mentioned PVA solution (solid content 10%) was slowly added, and the reaction was stirred at 70 ° C for 2 h, cooled to room temperature, the pH was adjusted to 8.0-8.5, purified water was added to adjust the solid content to 12%-14%, and stirred at room temperature for 15 min; 5 g of fungicide (isothiazolinone) was added, and the mixture was stirred at room temperature for 15 min. After stirring evenly, the material was collected to obtain the cylinder adhesive product.

[0032] Example 5

[0033] The reactor was cleaned, and 2.16 kg of purified water was added. Stirring was initiated, followed by the addition of 0.24 kg of PVA 17-88 solid. The mixture was stirred for 10 minutes, then heated to 80°C and stirred for 1 hour. The mixture was cooled to room temperature and the pH was adjusted to 9.0-9.5 to obtain a PVA solution with a 10% solids content, which was set aside. 3.58 kg of PA solution (34% solids content) was added to the reactor, stirring was initiated, the temperature was raised to 80°C, and 2.4 kg of PVA solution (10% solids content) was slowly added. The mixture was stirred at 80°C for 1 hour, cooled to room temperature, and the pH was adjusted to 8.0-8.5. Purified water was added to adjust the solids content to 12%-14%. The mixture was stirred at room temperature for 15 minutes, and 2 g of a fungicide (benzisothiazolinone) was added. The mixture was stirred at room temperature for 15 minutes. After stirring evenly, the mixture was collected to obtain the cylinder adhesive product.

[0034] Comparative Example 1

[0035] First, add 60.0 g of PA solution (solid content 38%) to the reaction flask, start stirring, raise the temperature to 80°C, add 3.0 g of urea, and react at 80°C with stirring for 2 h. Then cool to 50°C, slowly add 16.8 g of epichlorohydrin dropwise, and react at 50°C with stirring until the viscosity reaches 20-50 mPa·s. Adjust the pH to 4-5, and add 204.2 g of water to adjust the solid content of the product to 15%.

[0036] Comparative Example 2

[0037] A commercially available polyamide polyamine-epichlorohydrin resin adhesive was selected.

[0038] Test example

[0039] The advantages of the cylinder adhesive prepared by the present invention are reflected through some test experiments below:

[0040] (1) Testing the drying efficiency of adhesives: The same dosage of adhesive samples was examined and dried at the same temperature. The shorter the drying time, the higher the drying efficiency. The specific testing method is as follows: 4 mL of adhesive is pipetted onto a steel sheet, the adhesive is evenly applied with a brush, and then a kraft paper strip is attached to the adhesive. The adhesive is then placed in an oven at 80°C for drying, and the drying time is recorded.

[0041] (2) Test the adhesive strength of the adhesive: According to the 180° peel strength test method for adhesives in GB / T 2790-1995, use paper strips of the same size to stick to a steel sheet through the adhesive. After drying under the same conditions, test the force required to peel the paper strips on a tensile testing machine to test the adhesive performance. The specific method is as follows: clamp the steel sheet on a fixed chuck, bend the unbonded end of the flexible paper strip 180°, and clamp it on another chuck; during the test, pull the paper strip apart in a direction parallel to the steel sheet (180°). As the paper strip is gradually peeled off, record the separation distance of the chucks and the force applied when the chucks are separated. For each sample, measure the average peel force in N from the relationship curve between peel force and peel length.

[0042] The drying time and peeling force data of each embodiment and comparative example are shown in the following table:

[0043]

[0044] Analysis and Conclusion: The adhesives provided by the present invention (Examples 3, 4, and 5) exhibited short drying times, high peeling forces, and superior adhesive performance. The products corresponding to Examples 1 and 2, which are single components in the formulation, performed well when tested separately without the adhesive. The adhesives corresponding to Comparative Examples 1 and 2 demonstrated acceptable peeling forces, but required longer drying times. In summary, the adhesive products provided by the present invention exhibit rapid drying capabilities, making them suitable for use in high-speed paper machines. They can also reduce drying cylinder temperatures and steam energy consumption. Furthermore, it should be noted that conventional adhesives require extended drying times to exhibit effective adhesion. The present invention exhibits outstanding adhesion even with shorter drying times, demonstrating excellent adhesion across a wide range of dryness and humidity.

[0045] The above description is only a preferred embodiment of the present invention and is 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 scope of protection of the present invention.

Claims

1. A method for preparing a fast-drying cylinder adhesive, characterized in that: The steps include: S1. Preparation of polyamide-polyamine intermediate solution: Add diethylenetriamine to a four-necked flask, slowly add adipic acid to the reaction system with stirring, control the temperature at 150-180°C, and keep the reaction warm for 3-5 hours. After the reaction is complete, add purified water to adjust the solid content of the polyamide-polyamine intermediate to 30%-55%, adjust the pH to 8-10, and store the solution for later use. S2. Preparation of polyethylene solution: Heat purified water to 60-70°C with stirring. Add polyvinyl alcohol solid in batches and stir for 0.5-4 hours until the solid is completely dissolved. Cool to room temperature and adjust the pH to 8-10 with a pH adjuster to obtain a polyvinyl alcohol solution. S3. Preparation of cylinder adhesive: Add the polyamide polyamine intermediate solution to a four-necked flask, raise the temperature to 70-80°C, slowly add the polyvinyl alcohol solution while stirring, and after sufficient reaction, adjust the pH of the reaction solution to 6.5-10, add purified water to adjust the solid content to 12%-15%, and add a fungicide to obtain the cylinder adhesive.

2. The method for preparing a fast-drying cylinder adhesive according to claim 1, wherein: In step S1, the molar ratio of diethylenetriamine to adipic acid is 1:1.0-1.1, and the reaction time is 3-10 h.

3. The method for preparing a fast-drying cylinder adhesive according to claim 1, characterized in that: In step S2, the polyvinyl alcohol solid is any one of type 5-88 and type 17-88, or a mixture of the two.

4. The method for preparing a fast-drying cylinder adhesive according to claim 1, characterized in that: The concentration of the polyvinyl alcohol solution obtained in step S2 is 5% to 15%.

5. The method for preparing a fast-drying cylinder adhesive according to claim 1, characterized in that: In step S3, the mass ratio of polyvinyl alcohol to polyamide polyamine intermediate is 0.2-0.35:

1.

6. The method for preparing a fast-drying cylinder adhesive according to claim 1, characterized in that: In step S3, after the polyvinyl alcohol solution is added, the mixture is stirred and reacted for 1 to 5 hours.

7. The method for preparing a fast-drying cylinder adhesive according to claim 1, characterized in that: The fungicide added in step S3 is either one of isothiazolinone and benzisothiazolinone or a mixture of the two.

8. The method for preparing a fast-drying cylinder adhesive according to claim 7, characterized in that: The content of fungicide in the anti-tank agent is 100~500 ppm.

9. The method for preparing a fast-drying cylinder adhesive according to any one of claims 1 to 8, characterized in that: The pH regulator used in steps S1 and S2 is a mixture of any one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

10. A fast-drying cylinder adhesive, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 9.

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