Production methods for specialty paper

Abstract

The present invention belongs to the technical field of specialty paper preparation, and specifically relates to a method for producing specialty paper. The method for producing specialty paper of the present invention uses a compound of bleached sulfate masson pine pulp and bleached wheat straw pulp to construct a three-dimensional skeleton structure in which long and short fibers are interwoven, and uses modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres as fillers. The rigid skeleton of the modified calcium titanate whiskers and the flexible buffer of the modified magnesium borate whiskers form a stress gradient transmission, and the addition of polyacrylate microspheres can reduce local stress concentration. The three act synergistically to improve tensile strength and folding endurance. The high retention rate of acorn starch ensures that the filler is in full contact with the fiber, providing dense reaction sites for trans-aconitic acid crosslinking, thereby forming a water-resistant crosslinked network. Thus, the raw materials work synergistically to ensure that the produced specialty paper has excellent dry tensile strength, bursting resistance, folding endurance and wet strength retention rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of special paper preparation, and specifically relates to a production method of special paper. Background Art

[0002] Specialty paper is a general term for a type of paper designed for specialized applications, as opposed to ordinary paper. It is widely used in light industry, textiles, food, water conservancy, electricity, telecommunications, transportation, and construction. Specialty paper is primarily made from plant fibers, but synthetic fibers are also used to compensate for some of the weaknesses of natural fibers. When used as a papermaking raw material, synthetic fibers have a relatively smooth surface, poor water wettability, low surface activity, and difficulty achieving an ideal fiber diameter.

[0003] Furthermore, since fibers are primarily bonded together by hydrogen bonds, changes in temperature and humidity can affect these bonds, reducing the paper's strength, folding resistance, and water resistance. Improving the physical properties of specialty paper has become a pressing technical challenge. Therefore, it is necessary to explore a new method for producing specialty paper. Summary of the Invention

[0004] The object of the present invention is to provide a method for producing specialty paper. The specialty paper produced by the method has excellent dry tensile strength, bursting endurance, folding endurance and wet strength retention rate.

[0005] The method for producing specialty paper of the present invention comprises the following steps:

[0006] (1) Preparation of modified calcium titanate whiskers

[0007] The titanate coupling agent NDZ-201, anhydrous ethanol and deionized water were mixed, acetic acid was added to adjust the pH value of the reaction system to 4, and the mixture was stirred and dissolved at 38-40°C for 15 minutes to prepare a mixed solution, and then dried calcium titanate whiskers were added and stirred at 73-75°C for 1.5 hours. After standing, the mixture was centrifuged, washed and dried to prepare modified calcium titanate whiskers.

[0008] (2) Preparation of modified magnesium borate whiskers

[0009] N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water are uniformly mixed, and then hydrochloric acid is added to adjust the pH value of the system to 4.5 to prepare a mixed solution, which is allowed to stand for 5 minutes, hydrolyzed at 38-40° C. for 30 minutes, cooled to 23-25° C., added with magnesium borate whiskers and reacted for 45 minutes, allowed to stand, centrifuged, washed and dried to prepare modified magnesium borate whiskers;

[0010] (3) pulping and beating the bleached kraft masson pine pulp and the bleached wheat straw pulp respectively to obtain a slurry of the bleached kraft masson pine pulp and a slurry of the bleached wheat straw pulp, and then mixing the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry;

[0011] (4) adding acorn starch to the mixed slurry prepared in step (3) and stirring at room temperature, then sequentially adding modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres and stirring and mixing, adding acetic acid to adjust the pH value of the system to 5, and finally adding trans-aconitic acid and stirring and mixing to prepare a slurry;

[0012] (5) The obtained pulp is put on a screen for papermaking, pressed and dried at low temperature and high temperature to prepare special paper.

[0013] in:

[0014] In step (1), the mass ratio of titanate coupling agent NDZ-201, anhydrous ethanol, and deionized water is 3:1333:1.

[0015] In step (1), the mass of the titanate coupling agent NDZ-201 accounts for 2.0% of the mass of the dried calcium titanate whiskers.

[0016] The mass ratio of the dried calcium titanate whiskers to the mixed liquid in step (1) is 1:9.

[0017] The calcium titanate whiskers dried in step (1) are obtained by vacuum drying the calcium titanate whiskers at 105° C. for 3 hours.

[0018] The stirring speed during the preparation of modified calcium titanate whiskers in step (1) is 500 r / min.

[0019] The washing in step (1) is performed by eluting with hot ethanol at 60°C for 3 times, and the drying is performed by vacuum drying at 85°C for 1.5 hours.

[0020] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol, and deionized water is 1.2:786:100.5.

[0021] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0022] The mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in step (2) accounts for 1.35% of the mass of the magnesium borate whiskers.

[0023] The washing in step (2) is performed by rinsing with 5°C ethanol for 3 times, and the drying is performed by vacuum drying at 40°C for 4 hours.

[0024] In step (3), the manufacturer of the bleached sulfate masson pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of the bleached wheat straw pulp is Nanyang Tailong Paper Group Co., Ltd.

[0025] In step (3), the mass ratio of bleached sulfate masson pine pulp to bleached wheat straw pulp is 7-7.5:2.5-3.

[0026] In step (3), the beating degree of the bleached sulfate masson pine pulp is 38°SR, and the mass concentration of the bleached sulfate masson pine pulp solution is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp solution is 5%.

[0027] In step (4), acorn starch is added and stirred at room temperature for 15-17 minutes. The pH value of the reaction system is 7.

[0028] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres were added and stirred for 23-25 minutes at a stirring speed of 600 r / min.

[0029] The manufacturer of the polyacrylate microspheres in step (4) is Zhejiang Jingmai Polymer Materials Co., Ltd.

[0030] In step (4), the mass concentration of acetic acid is 1%. After adding trans-aconitic acid, the mixture is stirred for 10-12 minutes at a stirring speed of 400 r / min.

[0031] In step (4), the mass of the modified calcium titanate whiskers accounts for 3.5-4.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the modified magnesium borate whiskers accounts for 3.5-4.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the polyacrylate microspheres accounts for 2.5-3% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the acorn starch accounts for 1.6-1.8% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, and the mass of the trans-aconitic acid accounts for 1.0-1.2% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp.

[0032] In step (5), the pressing and drying pressure is 1.0 MPa, the low-temperature pressing and drying temperature is 85-88°C, the low-temperature pressing and drying time is 18-20 seconds, the high-temperature pressing and drying temperature is 153-155°C, and the high-temperature pressing and drying time is 40-42 seconds.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The method for producing specialty paper of the present invention comprises compounding bleached kraft masson pine pulp and bleached wheat straw pulp to construct a three-dimensional skeleton structure of interwoven long and short fibers. Modified calcium titanate whiskers, modified magnesium borate whiskers, and polyacrylate microspheres are used as fillers. The rigid skeleton of the modified calcium titanate whiskers and the flexible buffering of the modified magnesium borate whiskers form a stress gradient transmission. The addition of polyacrylate microspheres can reduce local stress concentration. The three act synergistically to improve tensile strength and folding endurance. The high retention rate of acorn starch ensures full contact between the filler and the fiber, providing dense reaction sites for trans-aconitic acid crosslinking, thereby forming a water-resistant crosslinked network. Thus, the synergistic effect between the raw materials ensures that the produced specialty paper has excellent dry tensile strength, bursting resistance, folding endurance, and wet strength retention.

[0035] (2) The method for producing special paper of the present invention comprises adding modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres as fillers. After the calcium titanate whiskers are modified, they penetrate the fiber network, inhibiting fiber slippage under external force, and their thermal expansion coefficient matches that of plant fibers, reducing thermal stress cracking, thereby improving the tensile strength of the paper. The magnesium borate whiskers contain BOB chemical bonds, and after modification, the amino groups can form a hydrogen bond network with the hydroxyl groups of cellulose. Therefore, the addition of the modified magnesium borate whiskers can improve the folding resistance of the paper and the strength retention rate in a wet state. The polyacrylate microspheres have suitable particle size and surface properties, can fill the gaps between paper fibers, and enhance the bonding force between the fibers. Thus, the three work synergistically to ensure that the prepared paper has excellent mechanical properties.

[0036] (3) In the production method of special paper described in the present invention, acorn starch is fully adsorbed on the fiber surface and the fiber binding force is enhanced through hydrogen bonding or electrostatic interaction. Acorn starch can improve the tensile strength of paper and at the same time improve the retention rate of pulp and better water filtration performance; acetic acid is added to adjust the pH value of the system to acidic, and pre-curing is achieved in the low temperature section, and then the high temperature section triggers the cross-linking of the five-membered ring anhydride, that is, the adjacent carboxyl groups in the trans-aconitic acid molecule are dehydrated under heating conditions to form a five-membered ring anhydride, and then the five-membered ring anhydride is opened and undergoes an esterification reaction with the hydroxyl groups in the cellulose molecule to form a -COO-fiber bond, thereby forming a three-dimensional network structure and locking the fiber, thereby significantly improving the wet strength of the paper.

[0037] (4) The production method of the special paper described in the present invention is to compound bleached sulfate masson pine pulp and bleached wheat straw pulp, with bleached sulfate masson pine pulp as the main component to ensure that the paper has a higher skeleton strength. At the same time, the compounding of wheat straw pulp makes the fiber interweaving more compact, thereby improving the burst resistance and folding resistance of the paper.

[0038] (5) The production method of the specialty paper described in the present invention has readily available raw materials, easy control of process parameters, and is easy to realize industrialized production. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the examples.

[0040] Example 1

[0041] The method for producing specialty paper described in Example 1 comprises the following steps:

[0042] (1) Preparation of modified calcium titanate whiskers

[0043] Titanate coupling agent NDZ-201, anhydrous ethanol and deionized water were mixed, acetic acid was added to adjust the pH value of the reaction system to 4, and the mixture was stirred and dissolved at 39°C for 15 minutes to prepare a mixed solution, and then dried calcium titanate whiskers were added and stirred at 74°C for 1.5 hours. After standing, the mixture was centrifuged, washed and dried to prepare modified calcium titanate whiskers.

[0044] (2) Preparation of modified magnesium borate whiskers

[0045] N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water were uniformly mixed, and then hydrochloric acid was added to adjust the pH value of the system to 4.5 to prepare a mixed solution, which was allowed to stand for 5 minutes, hydrolyzed at 39° C. for 30 minutes, cooled to 24° C., added with magnesium borate whiskers and reacted for 45 minutes. After standing, the solution was centrifuged, washed and dried to prepare modified magnesium borate whiskers.

[0046] (3) pulping and beating the bleached kraft masson pine pulp and the bleached wheat straw pulp respectively to obtain a slurry of the bleached kraft masson pine pulp and a slurry of the bleached wheat straw pulp, and then mixing the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry;

[0047] (4) adding acorn starch to the mixed slurry prepared in step (3) and stirring at room temperature, then sequentially adding modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres and stirring and mixing, adding acetic acid to adjust the pH value of the system to 5, and finally adding trans-aconitic acid and stirring and mixing to prepare a slurry;

[0048] (5) The obtained pulp is put on a screen for papermaking, pressed and dried at low temperature and high temperature to prepare special paper.

[0049] in:

[0050] In step (1), the mass ratio of titanate coupling agent NDZ-201, anhydrous ethanol, and deionized water is 3:1333:1.

[0051] In step (1), the mass of the titanate coupling agent NDZ-201 accounts for 2.0% of the mass of the dried calcium titanate whiskers.

[0052] The mass ratio of the dried calcium titanate whiskers to the mixed liquid in step (1) is 1:9.

[0053] The calcium titanate whiskers dried in step (1) are obtained by vacuum drying the calcium titanate whiskers at 105° C. for 3 hours.

[0054] The stirring speed during the preparation of modified calcium titanate whiskers in step (1) is 500 r / min.

[0055] The washing in step (1) is performed by eluting with hot ethanol at 60°C for 3 times, and the drying is performed by vacuum drying at 85°C for 1.5 hours.

[0056] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol, and deionized water is 1.2:786:100.5.

[0057] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0058] The mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in step (2) accounts for 1.35% of the mass of the magnesium borate whiskers.

[0059] The washing in step (2) is performed by rinsing with 5°C ethanol for 3 times, and the drying is performed by vacuum drying at 40°C for 4 hours.

[0060] In step (3), the manufacturer of the bleached sulfate masson pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of the bleached wheat straw pulp is Nanyang Tailong Paper Group Co., Ltd.

[0061] In step (3), the mass ratio of bleached sulfate masson pine pulp to bleached wheat straw pulp is 7:3.

[0062] In step (3), the beating degree of the bleached sulfate masson pine pulp is 38°SR, and the mass concentration of the bleached sulfate masson pine pulp solution is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp solution is 5%.

[0063] In step (4), acorn starch was added and stirred at room temperature for 16 minutes. The pH value of the reaction system was 7.

[0064] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres were added and stirred for 24 minutes at a stirring speed of 600 r / min.

[0065] The manufacturer of the polyacrylate microspheres in step (4) is Zhejiang Jingmai Polymer Materials Co., Ltd.

[0066] The mass concentration of acetic acid in step (4) is 1%. After adding trans-aconitic acid, the mixture is stirred for 11 minutes at a stirring speed of 400 r / min.

[0067] In step (4), the mass of the modified calcium titanate whiskers accounts for 4.0% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the modified magnesium borate whiskers accounts for 4.0% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the polyacrylate microspheres accounts for 2.7% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the acorn starch accounts for 1.7% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, and the mass of the trans-aconitic acid accounts for 1.1% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp.

[0068] In step (5), the pressing and drying pressure is 1.0 MPa, the low-temperature pressing and drying temperature is 86° C., the low-temperature pressing and drying time is 19 s, the high-temperature pressing and drying temperature is 154° C., and the high-temperature pressing and drying time is 41 s.

[0069] The specialty paper produced in Example 1 had a dry tensile strength of 50.5 kN / m, a bursting strength of 435 kPa, a folding endurance (MIT) of 2090 times, and a wet strength retention rate of 41.7%.

[0070] Example 2

[0071] The method for producing specialty paper described in Example 2 comprises the following steps:

[0072] (1) Preparation of modified calcium titanate whiskers

[0073] Titanate coupling agent NDZ-201, anhydrous ethanol and deionized water were mixed, acetic acid was added to adjust the pH value of the reaction system to 4, and the mixture was stirred and dissolved at 38°C for 15 minutes to prepare a mixed solution, and then dried calcium titanate whiskers were added and stirred at 73°C for 1.5 hours. After standing, the mixture was centrifuged, washed and dried to prepare modified calcium titanate whiskers.

[0074] (2) Preparation of modified magnesium borate whiskers

[0075] N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water were uniformly mixed, and then hydrochloric acid was added to adjust the pH value of the system to 4.5 to prepare a mixed solution, which was allowed to stand for 5 minutes, hydrolyzed at 40°C for 30 minutes, cooled to 25°C, added with magnesium borate whiskers and reacted for 45 minutes. After standing, the solution was centrifuged, washed and dried to prepare modified magnesium borate whiskers.

[0076] (3) pulping and beating the bleached kraft masson pine pulp and the bleached wheat straw pulp respectively to obtain a slurry of the bleached kraft masson pine pulp and a slurry of the bleached wheat straw pulp, and then mixing the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry;

[0077] (4) adding acorn starch to the mixed slurry prepared in step (3) and stirring at room temperature, then sequentially adding modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres and stirring and mixing, adding acetic acid to adjust the pH value of the system to 5, and finally adding trans-aconitic acid and stirring and mixing to prepare a slurry;

[0078] (5) The obtained pulp is put on a screen for papermaking, pressed and dried at low temperature and high temperature to prepare special paper.

[0079] in:

[0080] In step (1), the mass ratio of titanate coupling agent NDZ-201, anhydrous ethanol, and deionized water is 3:1333:1.

[0081] In step (1), the mass of the titanate coupling agent NDZ-201 accounts for 2.0% of the mass of the dried calcium titanate whiskers.

[0082] The mass ratio of the dried calcium titanate whiskers to the mixed liquid in step (1) is 1:9.

[0083] The calcium titanate whiskers dried in step (1) are obtained by vacuum drying the calcium titanate whiskers at 105° C. for 3 hours.

[0084] The stirring speed during the preparation of modified calcium titanate whiskers in step (1) is 500 r / min.

[0085] The washing in step (1) is performed by eluting with hot ethanol at 60°C for 3 times, and the drying is performed by vacuum drying at 85°C for 1.5 hours.

[0086] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol, and deionized water is 1.2:786:100.5.

[0087] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0088] The mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in step (2) accounts for 1.35% of the mass of the magnesium borate whiskers.

[0089] The washing in step (2) is performed by rinsing with 5°C ethanol for 3 times, and the drying is performed by vacuum drying at 40°C for 4 hours.

[0090] In step (3), the manufacturer of the bleached sulfate masson pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of the bleached wheat straw pulp is Nanyang Tailong Paper Group Co., Ltd.

[0091] In step (3), the mass ratio of bleached sulfate masson pine pulp to bleached wheat straw pulp is 7.5:2.5.

[0092] In step (3), the beating degree of the bleached sulfate masson pine pulp is 38°SR, and the mass concentration of the bleached sulfate masson pine pulp solution is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp solution is 5%.

[0093] In step (4), acorn starch was added and stirred at room temperature for 17 minutes. The pH value of the reaction system was 7.

[0094] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres were added and stirred for 23 minutes at a stirring speed of 600 r / min.

[0095] The manufacturer of the polyacrylate microspheres in step (4) is Zhejiang Jingmai Polymer Materials Co., Ltd.

[0096] The mass concentration of acetic acid in step (4) is 1%. After adding trans-aconitic acid, the mixture is stirred for 10 minutes at a stirring speed of 400 r / min.

[0097] In step (4), the mass of the modified calcium titanate whiskers accounts for 3.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the modified magnesium borate whiskers accounts for 4.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the polyacrylate microspheres accounts for 2.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the acorn starch accounts for 1.8% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, and the mass of the trans-aconitic acid accounts for 1.0% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp.

[0098] In step (5), the pressing and drying pressure is 1.0 MPa, the low-temperature pressing and drying temperature is 85° C., the low-temperature pressing and drying time is 20 s, the high-temperature pressing and drying temperature is 153° C., and the high-temperature pressing and drying time is 40 s.

[0099] The specialty paper produced in Example 2 had a dry tensile strength of 49.7 kN / m, a bursting strength of 427 kPa, a folding endurance (MIT) of 2020 times, and a wet strength retention rate of 40.8%.

[0100] Example 3

[0101] The method for producing specialty paper described in Example 3 comprises the following steps:

[0102] (1) Preparation of modified calcium titanate whiskers

[0103] Titanate coupling agent NDZ-201, anhydrous ethanol and deionized water were mixed, acetic acid was added to adjust the pH value of the reaction system to 4, and the mixture was stirred and dissolved at 40°C for 15 minutes to prepare a mixed solution, and then dried calcium titanate whiskers were added and stirred at 75°C for 1.5 hours. After standing, the mixture was centrifuged, washed and dried to prepare modified calcium titanate whiskers.

[0104] (2) Preparation of modified magnesium borate whiskers

[0105] N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water were mixed uniformly, and then hydrochloric acid was added to adjust the pH value of the system to 4.5 to prepare a mixed solution, which was allowed to stand for 5 minutes, hydrolyzed at 38° C. for 30 minutes, cooled to 23° C., added with magnesium borate whiskers and reacted for 45 minutes. After standing, the solution was centrifuged, washed and dried to prepare modified magnesium borate whiskers.

[0106] (3) pulping and beating the bleached kraft masson pine pulp and the bleached wheat straw pulp respectively to obtain a slurry of the bleached kraft masson pine pulp and a slurry of the bleached wheat straw pulp, and then mixing the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry;

[0107] (4) adding acorn starch to the mixed slurry prepared in step (3) and stirring at room temperature, then sequentially adding modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres and stirring and mixing, adding acetic acid to adjust the pH value of the system to 5, and finally adding trans-aconitic acid and stirring and mixing to prepare a slurry;

[0108] (5) The obtained pulp is put on a screen for papermaking, pressed and dried at low temperature and high temperature to prepare special paper.

[0109] in:

[0110] In step (1), the mass ratio of titanate coupling agent NDZ-201, anhydrous ethanol, and deionized water is 3:1333:1.

[0111] In step (1), the mass of the titanate coupling agent NDZ-201 accounts for 2.0% of the mass of the dried calcium titanate whiskers.

[0112] The mass ratio of the dried calcium titanate whiskers to the mixed liquid in step (1) is 1:9.

[0113] The calcium titanate whiskers dried in step (1) are obtained by vacuum drying the calcium titanate whiskers at 105° C. for 3 hours.

[0114] The stirring speed during the preparation of modified calcium titanate whiskers in step (1) is 500 r / min.

[0115] The washing in step (1) is performed by eluting with hot ethanol at 60°C for 3 times, and the drying is performed by vacuum drying at 85°C for 1.5 hours.

[0116] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol, and deionized water is 1.2:786:100.5.

[0117] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0118] The mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in step (2) accounts for 1.35% of the mass of the magnesium borate whiskers.

[0119] The washing in step (2) is performed by rinsing with 5°C ethanol for 3 times, and the drying is performed by vacuum drying at 40°C for 4 hours.

[0120] In step (3), the manufacturer of the bleached sulfate masson pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of the bleached wheat straw pulp is Nanyang Tailong Paper Group Co., Ltd.

[0121] In step (3), the mass ratio of bleached sulfate masson pine pulp to bleached wheat straw pulp is 7.3:2.7.

[0122] In step (3), the beating degree of the bleached sulfate masson pine pulp is 38°SR, and the mass concentration of the bleached sulfate masson pine pulp solution is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp solution is 5%.

[0123] In step (4), acorn starch was added and stirred at room temperature for 15 minutes. The pH value of the reaction system was 7.

[0124] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres were added and stirred for 25 minutes at a stirring speed of 600 r / min.

[0125] The manufacturer of the polyacrylate microspheres in step (4) is Zhejiang Jingmai Polymer Materials Co., Ltd.

[0126] The mass concentration of acetic acid in step (4) is 1%. After adding trans-aconitic acid, the mixture is stirred for 12 minutes at a stirring speed of 400 r / min.

[0127] In step (4), the mass of the modified calcium titanate whiskers accounts for 4.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the modified magnesium borate whiskers accounts for 3.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the polyacrylate microspheres accounts for 3% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the acorn starch accounts for 1.6% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, and the mass of the trans-aconitic acid accounts for 1.2% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp.

[0128] In step (5), the pressing and drying pressure is 1.0 MPa, the low-temperature pressing and drying temperature is 88° C., the low-temperature pressing and drying time is 18 s, the high-temperature pressing and drying temperature is 155° C., and the high-temperature pressing and drying time is 42 s.

[0129] The specialty paper prepared in Example 3 had a dry tensile strength of 51.2 kN / m, a bursting strength of 440 kPa, a folding endurance (MIT) of 2150 times, and a wet strength retention rate of 42.8%.

[0130] Comparative Example 1

[0131] The method for producing the specialty paper described in Comparative Example 1 is the same as that in Example 1, except that modified calcium titanate whiskers are not added in step (4). The specialty paper produced in Comparative Example 1 has a dry tensile strength of 43.2 kN / m, a bursting strength of 365 kPa, a folding endurance (MIT) of 1950 times, and a wet strength retention rate of 40.1%.

[0132] Comparative Example 2

[0133] The method for producing the specialty paper described in Comparative Example 2 is the same as that in Example 1, except that modified magnesium borate whiskers are not added in step (4). The specialty paper produced in Comparative Example 2 has a dry tensile strength of 47.6 kN / m, a bursting strength of 390 kPa, a folding endurance (MIT) of 1210 times, and a wet strength retention rate of 38.5%.

[0134] Comparative Example 3

[0135] The method for producing the specialty paper described in Comparative Example 3 is the same as that in Example 1, except that no polyacrylate microspheres are added in step (4). The specialty paper produced in Comparative Example 3 has a dry tensile strength of 46.8 kN / m, a bursting strength of 381 kPa, a folding endurance (MIT) of 1750 times, and a wet strength retention rate of 39.3%.

[0136] Comparative Example 4

[0137] The method for producing the specialty paper described in Comparative Example 4 is the same as that in Example 1, except that trans-aconitic acid is not added for cross-linking in step (4). The specialty paper produced in Comparative Example 4 has a dry tensile strength of 48.2 kN / m, a bursting strength of 402 kPa, a folding endurance (MIT) of 1940 times, and a wet strength retention rate of 12.5%.

[0138] As can be seen, the performance of the specialty paper produced in Examples 1-3 is superior to that of Comparative Examples 1-4. Specifically, the absence of modified calcium titanate whiskers in Comparative Example 1 significantly reduces the tensile strength of the specialty paper produced, the absence of modified magnesium borate whiskers in Comparative Example 2 significantly reduces the folding endurance of the specialty paper produced, the absence of polyacrylate microspheres in Comparative Example 3 reduces both the tensile strength and folding endurance of the specialty paper produced, and the absence of trans-aconitic acid for cross-linking in Comparative Example 4 significantly reduces the wet strength retention of the specialty paper produced.

Claims

1. A method for producing specialty paper, characterized in that: It consists of the following steps: (1) Preparation of modified calcium titanate whiskers The titanate coupling agent NDZ-201, anhydrous ethanol and deionized water were mixed, acetic acid was added to adjust the pH value of the reaction system to 4, and the mixture was stirred and dissolved at 38-40°C for 15 minutes to prepare a mixed solution, and then dried calcium titanate whiskers were added and stirred at 73-75°C for 1.5 hours. After standing, the mixture was centrifuged, washed and dried to prepare modified calcium titanate whiskers. (2) Preparation of modified magnesium borate whiskers N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol and deionized water are uniformly mixed, and then hydrochloric acid is added to adjust the pH value of the system to 4.5 to prepare a mixed solution, which is allowed to stand for 5 minutes, hydrolyzed at 38-40° C. for 30 minutes, cooled to 23-25° C., added with magnesium borate whiskers and reacted for 45 minutes, allowed to stand, centrifuged, washed and dried to prepare modified magnesium borate whiskers; (3) pulping and beating the bleached kraft masson pine pulp and the bleached wheat straw pulp respectively to obtain a slurry of the bleached kraft masson pine pulp and a slurry of the bleached wheat straw pulp, and then mixing the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry; (4) adding acorn starch to the mixed slurry prepared in step (3) and stirring at room temperature, then sequentially adding modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres and stirring and mixing, adding acetic acid to adjust the pH value of the system to 5, and finally adding trans-aconitic acid and stirring and mixing to prepare a slurry; (5) The obtained pulp is put on a screen for papermaking, pressed and dried at low temperature and high temperature to prepare special paper.

2. The method for producing specialty paper according to claim 1, wherein: In step (1), the mass ratio of titanate coupling agent NDZ-201, anhydrous ethanol, and deionized water is 3:1333:1; In step (1), the mass of the titanate coupling agent NDZ-201 accounts for 2.0% of the mass of the dried calcium titanate whiskers; The mass ratio of the dried calcium titanate whiskers to the mixed liquid in step (1) is 1:

9.

3. The method for producing specialty paper according to claim 1, wherein: The calcium titanate whiskers dried in step (1) are obtained by vacuum drying the calcium titanate whiskers at 105° C. for 3 hours; During the preparation of modified calcium titanate whiskers in step (1), the stirring speed is 500 r / min; The washing in step (1) is performed by eluting with hot ethanol at 60°C for 3 times, and the drying is performed by vacuum drying at 85°C for 1.5 hours.

4. The method for producing specialty paper according to claim 1, wherein: In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, anhydrous ethanol, and deionized water is 1.2:786:100.5; In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:

10.

5. The method for producing specialty paper according to claim 1, wherein: In step (2), the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane accounts for 1.35% of the mass of the magnesium borate whiskers; The washing in step (2) is performed by rinsing with 5°C ethanol for 3 times, and the drying is performed by vacuum drying at 40°C for 4 hours.

6. The method for producing specialty paper according to claim 1, wherein: In step (3), the mass ratio of bleached kraft masson pine pulp to bleached wheat straw pulp is 7-7.5:2.5-3; In step (3), the beating degree of the bleached sulfate masson pine pulp is 38°SR, and the mass concentration of the bleached sulfate masson pine pulp solution is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp solution is 5%.

7. The method for producing specialty paper according to claim 1, wherein: In step (4), acorn starch is added and stirred at room temperature for 15-17 minutes, and the pH value of the reaction system is 7; In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres were added and stirred for 23-25 minutes at a stirring speed of 600 r / min.

8. The method for producing specialty paper according to claim 1, wherein: In step (4), the mass concentration of acetic acid is 1%. After adding trans-aconitic acid, the mixture is stirred for 10-12 minutes at a stirring speed of 400 r / min.

9. The method for producing specialty paper according to claim 1, wherein: In step (4), the mass of the modified calcium titanate whiskers accounts for 3.5-4.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the modified magnesium borate whiskers accounts for 3.5-4.5% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the polyacrylate microspheres accounts for 2.5-3% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, the mass of the acorn starch accounts for 1.6-1.8% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp, and the mass of the trans-aconitic acid accounts for 1.0-1.2% of the total mass of the bleached sulfate masson pine pulp and the bleached wheat straw pulp.

10. The method for producing specialty paper according to claim 1, wherein: In step (5), the pressing and drying pressure is 1.0 MPa, the low-temperature pressing and drying temperature is 85-88°C, the low-temperature pressing and drying time is 18-20 seconds, the high-temperature pressing and drying temperature is 153-155°C, and the high-temperature pressing and drying time is 40-42 seconds.