Production method of specialty paper

Abstract

The invention belongs to the technical field of preparation of specialty paper, and particularly relates to a production method of specialty paper. According to the production method of the specialty paper, the bleached sulfate masson pine pulp and the bleached wheat straw pulp are compounded for use, a long-short fiber interlaced three-dimensional skeleton structure is constructed, modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres are used as fillers, and the special paper is prepared by compounding the modified calcium titanate whiskers, the modified magnesium borate whiskers and the polyacrylate microspheres. The rigid framework of the modified calcium titanate whisker and the flexible buffering of the modified magnesium borate whisker form stress gradient transfer, the addition of the polyacrylate microspheres can reduce local stress concentration, the synergistic effect of the three can improve the tensile strength and folding strength, and the high retention rate of the acorn starch can ensure that the filler is in full contact with fibers. A compact reaction site is provided for trans-aconitic acid cross-linking, so that a water-resistant cross-linked network is formed. Therefore, through the synergistic effect of the raw materials, it is ensured that the produced specialty paper has excellent dry tensile strength, bursting strength, folding strength 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] Special paper is a general term for a class of papers with special uses as opposed to ordinary paper. Special paper has been widely used in industries such as light industry, textile, food, water conservancy, electric power, telecommunications, transportation, and construction. The raw materials of special paper are mostly plant fibers. In addition to plant fibers, synthetic fibers and other raw materials are also used to make up for some weaknesses of natural fibers. When synthetic fibers are used as papermaking raw materials, due to their relatively smooth surface, poor wettability to water, low surface activity, it is difficult to form an ideal combination of fiber diameters.

[0003] And since the fibers are mainly bonded by hydrogen bonds, changes in temperature and humidity will affect the hydrogen bonds, resulting in a decrease in the strength, folding resistance, and water resistance of the paper. How to improve the physical properties of special paper has become an urgent technical problem to be studied and solved currently. Therefore, it is necessary to explore a new production method for special paper. Summary of the Invention

[0004] The object of the present invention is to provide a production method of special paper. The special paper produced by this method has excellent dry tensile strength, burst strength, folding endurance, and wet strength retention rate.

[0005] The production method of the special paper described in the present invention consists of the following steps: (1) Preparation of modified calcium titanate whiskers Mix titanate coupling agent NDZ-201, absolute ethanol, and deionized water, add acetic acid to adjust the pH value of the reaction system to 4, stir and dissolve at 38 - 40 °C for 15 min to obtain a mixed solution, then add dry calcium titanate whiskers and stir and react at 73 - 75 °C for 1.5 h. After standing, centrifuge, wash, and dry to prepare modified calcium titanate whiskers; (2) Preparation of modified magnesium borate whiskers Mix N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol, and deionized water evenly, then add hydrochloric acid to adjust the pH value of the system to 4.5 to obtain a mixed solution, let it stand for 5 min, hydrolyze at 38 - 40 °C for 30 min, cool down to 23 - 25 °C, add magnesium borate whiskers and react for 45 min. After standing, centrifuge, wash, and dry to prepare modified magnesium borate whiskers; (3) Pulping and beating the bleached kraft pine pulp and bleached wheat straw pulp respectively to obtain the slurry of bleached kraft pine pulp and the slurry of bleached wheat straw pulp, and then mix the slurry of bleached kraft pine pulp and the slurry of bleached wheat straw pulp to prepare a mixed slurry; (4) Add acorn starch to the mixed slurry prepared in step (3), stir and mix at room temperature, then sequentially add modified calcium titanate whiskers, modified magnesium borate whiskers, and polyacrylate microspheres and stir and mix them. Add acetic acid to adjust the pH value of the system to 5, and finally add trans-aconitic acid and stir and mix to prepare a slurry; (5) Sheet the obtained slurry on a wire, press and dry it at low temperature and then at high temperature to prepare a special paper.

[0006] Among them: In step (1), the mass ratio of titanate coupling agent NDZ-201, absolute ethanol, and deionized water is 3:1333:1.

[0007] In step (1), the mass of titanate coupling agent NDZ-201 accounts for 2.0% of the mass of dried calcium titanate whiskers.

[0008] In step (1), the mass ratio of dried calcium titanate whiskers to the mass of the mixed solution is 1:9.

[0009] In step (1), the dried calcium titanate whiskers are obtained by vacuum drying calcium titanate whiskers at 105 °C for 3 h.

[0010] In step (1), the stirring speed during the preparation of the modified calcium titanate whiskers is 500 r / min.

[0011] In step (1), the washing is carried out by rinsing 3 times with hot ethanol at 60 °C, and the drying is carried out by vacuum drying at 85 °C for 1.5 h.

[0012] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol, and deionized water is 1.2:786:100.5.

[0013] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0014] In step (2), the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane accounts for 1.35% of the mass of magnesium borate whiskers.

[0015] In step (2), the washing is carried out by rinsing 3 times with ethanol at 5 °C, and the drying is carried out by vacuum drying at 40 °C for 4 h.

[0016] In step (3), the manufacturer of bleached kraft masson pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of bleached wheat straw pulp is Nanyang Tailong Paper Industry Group Co., Ltd.

[0017] In step (3), the mass ratio of bleached kraft masson pine pulp to bleached wheat straw pulp is 7 - 7.5:2.5 - 3.

[0018] In step (3), the beating degree of the bleached kraft masson pine pulp is 38°SR, and the mass concentration of the bleached kraft masson pine pulp slurry is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp slurry is 5%.

[0019] In step (4), acorn starch is added and stirred and mixed at room temperature for 15 - 17 min, and the pH value of the reaction system is 7.

[0020] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres are added and stirred and mixed for 23 - 25 min, and the stirring speed is 600 r / min.

[0021] In step (4), the manufacturer of the polyacrylate microspheres is Zhejiang Jingmai High Polymer Materials Co., Ltd.

[0022] In step (4), the mass concentration of acetic acid is 1%. After adding trans - aconitic acid, it is stirred and mixed for 10 - 12 min, and the stirring speed is 400 r / min.

[0023] In step (4), the mass of the modified calcium titanate whiskers accounts for 3.5 - 4.5% of the total mass of the bleached kraft 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 kraft 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 kraft 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 kraft 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 kraft masson pine pulp and the bleached wheat straw pulp.

[0024] In step (5), the pressing and drying pressure is 1.0 MPa, the temperature of low - temperature pressing and drying is 85 - 88 °C, the time of low - temperature pressing and drying is 18 - 20 s, the temperature of high - temperature pressing and drying is 153 - 155 °C, and the time of high - temperature pressing and drying is 40 - 42 s.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1)The production method of the special paper of the present invention uses bleached kraft masson pine pulp and bleached wheat straw pulp in combination to construct a three-dimensional skeleton structure of long-short fiber interweaving. Using 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 transfer. The addition of polyacrylate microspheres can reduce local stress concentration. The synergistic effect of the three improves the tensile strength and folding endurance. The high retention rate of acorn starch ensures sufficient contact between the filler and the fiber, providing dense reaction sites for trans-aconitic acid crosslinking, thereby forming a water-resistant crosslinking network. Thus, through the synergistic effect between the raw materials, the special paper produced is ensured to have excellent dry tensile strength, bursting strength, folding endurance and wet strength retention rate.

[0026] (2)The production method of the special paper of the present invention adds modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres as fillers. After being modified, the calcium titanate whiskers penetrate the fiber network, inhibit the fiber slippage under external force, and have a thermal expansion coefficient matching that of plant fibers, reducing thermal stress cracking, thereby improving the tensile strength of the paper; the magnesium borate whiskers contain B-O-B chemical bonds, and after being modified, hydrogen bond networks can be formed between the amino groups and the hydroxyl groups of cellulose. Therefore, the addition of modified magnesium borate whiskers can improve the folding endurance and strength retention rate in the wet state of the paper. The polyacrylate microspheres have appropriate particle sizes and surface properties, can fill the voids between the paper fibers, and enhance the bonding force between the fibers. Thus, through the synergistic effect among the three, the prepared paper has good mechanical properties.

[0027] (3)The production method of the special paper of the present invention is that acorn starch is fully adsorbed on the fiber surface, enhancing the fiber bonding force through hydrogen bonds or electrostatic interactions. Acorn starch can improve the tensile strength of the paper and at the same time increase the retention rate of the pulp, with better drainage performance; acetic acid is added to adjust the pH value of the system to be acidic, pre-curing is achieved at a low temperature section, and then five-membered ring anhydride crosslinking is triggered at a high temperature section. That is, the adjacent carboxyl groups in the trans-aconitic acid molecule dehydrate under heating conditions to form a five-membered ring anhydride, and then the five-membered ring anhydride opens the ring and undergoes an esterification reaction with the hydroxyl groups in the cellulose molecule to form -COO-fiber bonds, thereby forming a three-dimensional network structure to lock the fibers, and thus significantly improving the wet strength of the paper.

[0028] (4)The production method of the special paper of the present invention uses bleached kraft masson pine pulp and bleached wheat straw pulp in combination, with bleached kraft masson pine pulp as the main component to ensure that the paper has a high skeleton strength. At the same time, using wheat straw pulp in combination makes the fiber interweaving more compact, improving the bursting strength and folding endurance of the paper.

[0029] (5)The production method of the special paper of the present invention has easily available raw materials, process parameters are easy to control, and industrial production is easy to achieve. Detailed implementation manners

[0030] The present invention will be further described below in conjunction with embodiments.

[0031] Embodiment 1 The production method of the special paper described in this Embodiment 1 consists of the following steps: (1) Preparation of modified calcium titanate whiskers Mix a titanate coupling agent NDZ-201, absolute ethanol, and deionized water, add acetic acid to adjust the pH value of the reaction system to 4, stir and dissolve at 39°C for 15 min to obtain a mixed solution, then add dry calcium titanate whiskers and stir and react at 74°C for 1.5 h. After standing, centrifuge, wash, and dry to prepare modified calcium titanate whiskers; (2) Preparation of modified magnesium borate whiskers Mix N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol, and deionized water evenly, then add hydrochloric acid to adjust the pH value of the system to 4.5 to obtain a mixed solution, let it stand for 5 min, hydrolyze at 39°C for 30 min, cool to 24°C, add magnesium borate whiskers and react for 45 min. After standing, centrifuge, wash, and dry to prepare modified magnesium borate whiskers; (3) Pulping and beating the bleached sulfate masson pine pulp and the bleached wheat straw pulp respectively to obtain the slurry of the bleached sulfate masson pine pulp and the slurry of the bleached wheat straw pulp, and then mix the slurry of the bleached sulfate masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry; (4) Add acorn starch to the mixed slurry prepared in step (3) and stir and mix at room temperature, then successively add modified calcium titanate whiskers, modified magnesium borate whiskers, and polyacrylate microspheres and stir and mix, add acetic acid to adjust the pH value of the system to 5, and finally add trans-aconitic acid and stir and mix to prepare a pulp; (5) Make the obtained pulp go through wire forming, low-temperature and high-temperature pressing and drying to prepare the special paper.

[0032] Wherein: In step (1), the mass ratio of the titanate coupling agent NDZ-201, absolute ethanol, and deionized water is 3:1333:1.

[0033] In step (1), the mass of the titanate coupling agent NDZ-201 accounts for 2.0% of the mass of the dry calcium titanate whiskers.

[0034] In step (1), the mass ratio of the dry calcium titanate whiskers to the mass of the mixed solution is 1:9.

[0035] In step (1), the dry calcium titanate whiskers are obtained by vacuum drying calcium titanate whiskers at 105°C for 3 h.

[0036] In step (1), the stirring speed during the preparation of the modified calcium titanate whiskers is 500 r / min.

[0037] In step (1), the washing is carried out by rinsing three times with hot ethanol at 60 °C, and the drying is carried out in vacuum at 85 °C for 1.5 h.

[0038] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol, and deionized water is 1.2 : 786 : 100.5.

[0039] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0040] In step (2), the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane accounts for 1.35% of the mass of magnesium borate whiskers.

[0041] In step (2), the washing is carried out by rinsing three times with ethanol at 5 °C, and the drying is carried out in vacuum at 40 °C for 4 h.

[0042] In step (3), the manufacturer of the bleached kraft pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of the bleached wheat straw pulp is Nanyang Tailong Paper Industry Group Co., Ltd.

[0043] In step (3), the mass ratio of the bleached kraft pine pulp to the bleached wheat straw pulp is 7 : 3.

[0044] In step (3), the beating degree of the bleached kraft pine pulp is 38 °SR, and the mass concentration of the bleached kraft pine pulp slurry is 20%; the beating degree of the bleached wheat straw pulp is 29 °SR, and the mass concentration of the bleached wheat straw pulp slurry is 5%.

[0045] In step (4), acorn starch is added and stirred and mixed at room temperature for 16 min, and the pH value of the reaction system is 7.

[0046] In step (4), the modified calcium titanate whiskers, the modified magnesium borate whiskers, and the polyacrylate microspheres are added and stirred and mixed for 24 min, and the stirring speed is 600 r / min.

[0047] In step (4), the manufacturer of the polyacrylate microspheres is Zhejiang Jingmai High Polymer Materials Co., Ltd.

[0048] In step (4), the mass concentration of acetic acid is 1%, and after adding trans-aconitic acid, it is stirred and mixed for 11 min, and the stirring speed is 400 r / min.

[0049] In step (4), the mass of the modified calcium titanate whiskers accounts for 4.0% of the total mass of the bleached kraft 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 kraft 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 kraft 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 kraft 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 kraft masson pine pulp and the bleached wheat straw pulp.

[0050] In step (5), the pressing and drying pressure is 1.0 MPa, the temperature of the low-temperature pressing and drying is 86 °C, the time of the low-temperature pressing and drying is 19 s, the temperature of the high-temperature pressing and drying is 154 °C, and the time of the high-temperature pressing and drying is 41 s.

[0051] The dry tensile strength of the special paper produced in Example 1 is 50.5 kN / m, the bursting strength is 435 kPa, the folding endurance (MIT) is 2090 times, and the wet strength retention rate is 41.7%.

[0052] Example 2 The production method of the special paper described in this Example 2 consists of the following steps: (1) Preparation of modified calcium titanate whiskers Mix the titanate coupling agent NDZ-201, absolute ethanol and deionized water, add acetic acid to adjust the pH value of the reaction system to 4, stir and dissolve at 38 °C for 15 min to obtain a mixed solution, then add dry calcium titanate whiskers and stir and react at 73 °C for 1.5 h. After standing, centrifuge, wash and dry to prepare the modified calcium titanate whiskers; (2) Preparation of modified magnesium borate whiskers Mix N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol and deionized water evenly, then add hydrochloric acid to adjust the pH value of the system to 4.5 to obtain a mixed solution, stand for 5 min, hydrolyze at 40 °C for 30 min, cool to 25 °C and add magnesium borate whiskers to react for 45 min. After standing, centrifuge, wash and dry to prepare the modified magnesium borate whiskers; (3) Pulping and beating the bleached kraft masson pine pulp and the bleached wheat straw pulp respectively to obtain the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp, and then mix the slurry of the bleached kraft masson pine pulp and the slurry of the bleached wheat straw pulp to prepare a mixed slurry; (4) Add acorn starch to the mixed slurry prepared in step (3) and stir and mix at room temperature, then sequentially add the modified calcium titanate whiskers, the modified magnesium borate whiskers and the polyacrylate microspheres and stir and mix, add acetic acid to adjust the pH value of the system to 5, and finally add trans-aconitic acid and stir and mix to prepare a pulp; (5) The obtained slurry is formed into paper by wire drawing, and then pressed and dried at low temperature and high temperature to prepare special paper.

[0053] Among them: In step (1), the mass ratio of titanate coupling agent NDZ-201, absolute ethanol, and deionized water is 3:1333:1.

[0054] In step (1), the mass of titanate coupling agent NDZ-201 accounts for 2.0% of the mass of dried calcium titanate whiskers.

[0055] In step (1), the mass ratio of dried calcium titanate whiskers to the mixed solution is 1:9.

[0056] In step (1), the dried calcium titanate whiskers are obtained by vacuum drying calcium titanate whiskers at 105 °C for 3 h.

[0057] In step (1), the stirring speed during the preparation of modified calcium titanate whiskers is 500 r / min.

[0058] In step (1), the washing is carried out by rinsing three times with hot ethanol at 60 °C, and the drying is carried out by vacuum drying at 85 °C for 1.5 h.

[0059] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol, and deionized water is 1.2:786:100.5.

[0060] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0061] In step (2), the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane accounts for 1.35% of the mass of magnesium borate whiskers.

[0062] In step (2), the washing is carried out by rinsing three times with ethanol at 5 °C, and the drying is carried out by vacuum drying at 40 °C for 4 h.

[0063] In step (3), the manufacturer of bleached kraft masson pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of bleached wheat straw pulp is Nanyang Tailong Paper Industry Group Co., Ltd.

[0064] In step (3), the mass ratio of bleached kraft masson pine pulp to bleached wheat straw pulp is 7.5:2.5.

[0065] In step (3), the beating degree of bleached kraft masson pine pulp is 38 °SR, and the mass concentration of the bleached kraft masson pine pulp slurry is 20%; the beating degree of bleached wheat straw pulp is 29 °SR, and the mass concentration of the bleached wheat straw pulp slurry is 5%.

[0066] In step (4), acorn starch was added and stirred at room temperature for 17 min, and the pH value of the reaction system was 7.

[0067] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres were added and stirred for 23 min at a stirring speed of 600 r / min.

[0068] In step (4), the manufacturer of the polyacrylate microspheres was Zhejiang Jingmai High Polymer Materials Co., Ltd.

[0069] In step (4), the mass concentration of acetic acid was 1%, and after adding trans-aconitic acid, it was stirred for 10 min at a stirring speed of 400 r / min.

[0070] In step (4), the mass of the modified calcium titanate whiskers accounted for 3.5% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, the mass of the modified magnesium borate whiskers accounted for 4.5% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, the mass of the polyacrylate microspheres accounted for 2.5% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, the mass of the acorn starch accounted for 1.8% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, and the mass of the trans-aconitic acid accounted for 1.0% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp.

[0071] In step (5), the pressing and drying pressure was 1.0 MPa, the temperature of low-temperature pressing and drying was 85 °C, the time of low-temperature pressing and drying was 20 s, the temperature of high-temperature pressing and drying was 153 °C, and the time of high-temperature pressing and drying was 40 s.

[0072] The dry tensile strength of the special paper produced in Example 2 was 49.7 kN / m, the bursting strength was 427 kPa, the folding endurance (MIT) was 2020 times, and the wet strength retention rate was 40.8%.

[0073] Example 3 The production method of the special paper described in this Example 3 consists of the following steps: (1) Preparation of modified calcium titanate whiskers The titanate coupling agent NDZ-201, absolute ethanol and deionized water were mixed evenly, acetic acid was added to adjust the pH value of the reaction system to 4, and it was stirred and dissolved at 40 °C for 15 min to obtain a mixed solution. Then, dry calcium titanate whiskers were added and stirred at 75 °C for 1.5 h. After standing, it was centrifuged, washed and dried to prepare modified calcium titanate whiskers; (2) Preparation of modified magnesium borate whiskers Mix N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol and deionized water evenly, then add hydrochloric acid to adjust the pH value of the system to 4.5 to prepare a mixed solution. Let it stand for 5 min, hydrolyze at 38 °C for 30 min, cool down to 23 °C, add magnesium borate whiskers and react for 45 min. After standing, centrifuge, wash and dry to prepare modified magnesium borate whiskers; (3)Carry out pulping and beating treatments on bleached kraft pine pulp and bleached wheat straw pulp respectively to obtain the slurry of bleached kraft pine pulp and the slurry of bleached wheat straw pulp, and then mix the slurry of bleached kraft pine pulp and the slurry of bleached wheat straw pulp to prepare a mixed slurry; (4)Add acorn starch to the mixed slurry prepared in step (3) and stir and mix at room temperature, then successively add modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres and stir and mix. Add acetic acid to adjust the pH value of the system to 5, and finally add trans-aconitic acid and stir and mix to prepare a pulp; (5)Make the obtained pulp go through wire drawing, low-temperature and high-temperature pressing and drying to prepare special paper.

[0074] Among them: In step (1), the mass ratio of titanate coupling agent NDZ-201, absolute ethanol and deionized water is 3:1333:1.

[0075] In step (1), the mass of titanate coupling agent NDZ-201 accounts for 2.0% of the mass of dry calcium titanate whiskers.

[0076] In step (1), the mass ratio of dry calcium titanate whiskers to the mixed solution is 1:9.

[0077] In step (1), the dry calcium titanate whiskers are obtained by vacuum drying calcium titanate whiskers at 105 °C for 3 h.

[0078] In step (1), the stirring speed during the preparation of modified calcium titanate whiskers is 500 r / min.

[0079] In step (1), the washing is carried out by rinsing 3 times with hot ethanol at 60 °C, and the drying is carried out by vacuum drying at 85 °C for 1.5 h.

[0080] In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol and deionized water is 1.2:786:100.5.

[0081] In step (2), the mass ratio of magnesium borate whiskers to the mixed solution is 1:10.

[0082] In step (2), the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane accounts for 1.35% of the mass of magnesium borate whiskers.

[0083] In step (2), the washing is carried out by rinsing 3 times with ethanol at 5°C, and the drying is carried out by vacuum drying at 40°C for 4 h.

[0084] In step (3), the manufacturer of bleached kraft pine pulp is Hunan Juntai Pulp and Paper Co., Ltd., and the manufacturer of bleached wheat straw pulp is Nanyang Tailong Paper Industry Group Co., Ltd.

[0085] In step (3), the mass ratio of bleached kraft pine pulp to bleached wheat straw pulp is 7.3 : 2.7.

[0086] In step (3), the beating degree of bleached kraft pine pulp is 38°SR, and the mass concentration of the bleached kraft pine pulp slurry is 20%; the beating degree of bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp slurry is 5%.

[0087] In step (4), acorn starch is added and stirred and mixed at room temperature for 15 min, and the pH value of the reaction system is 7.

[0088] In step (4), modified calcium titanate whiskers, modified magnesium borate whiskers and polyacrylate microspheres are added and stirred and mixed for 25 min, and the stirring speed is 600 r / min.

[0089] In step (4), the manufacturer of polyacrylate microspheres is Zhejiang Jingmai High Polymer Materials Co., Ltd.

[0090] In step (4), the mass concentration of acetic acid is 1%, after adding trans-aconitic acid, it is stirred and mixed for 12 min, and the stirring speed is 400 r / min.

[0091] In step (4), the mass of modified calcium titanate whiskers accounts for 4.5% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, the mass of modified magnesium borate whiskers accounts for 3.5% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, the mass of polyacrylate microspheres accounts for 3% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, the mass of acorn starch accounts for 1.6% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp, and the mass of trans-aconitic acid accounts for 1.2% of the total mass of bleached kraft pine pulp and bleached wheat straw pulp.

[0092] In step (5), the pressing and drying pressure is 1.0 MPa, the temperature of low-temperature pressing and drying is 88°C, the time of low-temperature pressing and drying is 18 s, the temperature of high-temperature pressing and drying is 155°C, and the time of high-temperature pressing and drying is 42 s.

[0093] The dry tensile strength of the special paper prepared in Example 3 is 51.2 kN / m, the bursting strength is 440 kPa, the folding endurance (MIT) is 2,150 times, and the wet strength retention rate is 42.8%.

[0094] Comparative Example 1 The production method of the special paper described in this Comparative Example 1 is the same as that of Example 1. The only difference is that in step (4), modified calcium titanate whiskers are not added. The dry tensile strength of the special paper produced in Comparative Example 1 is 43.2 kN / m, the bursting strength is 365 kPa, the folding endurance (MIT) is 1,950 times, and the wet strength retention rate is 40.1%.

[0095] Comparative Example 2 The production method of the special paper described in this Comparative Example 2 is the same as that of Example 1. The only difference is that in step (4), modified magnesium borate whiskers are not added. The dry tensile strength of the special paper produced in Comparative Example 2 is 47.6 kN / m, the bursting strength is 390 kPa, the folding endurance (MIT) is 1,210 times, and the wet strength retention rate is 38.5%.

[0096] Comparative Example 3 The production method of the special paper described in this Comparative Example 3 is the same as that of Example 1. The only difference is that in step (4), polyacrylate microspheres are not added. The dry tensile strength of the special paper produced in Comparative Example 3 is 46.8 kN / m, the bursting strength is 381 kPa, the folding endurance (MIT) is 1,750 times, and the wet strength retention rate is 39.3%.

[0097] Comparative Example 4 The production method of the special paper described in this Comparative Example 4 is the same as that of Example 1. The only difference is that in step (4), trans-aconitic acid is not added for cross-linking. The dry tensile strength of the special paper produced in Comparative Example 4 is 48.2 kN / m, the bursting strength is 402 kPa, the folding endurance (MIT) is 1,940 times, and the wet strength retention rate is 12.5%.

[0098] It can be seen from this that the performance of the special paper produced in Examples 1-3 is superior to that of Comparative Examples 1-4. Among them, the absence of modified calcium titanate whiskers in Comparative Example 1 results in a significant decrease in the tensile strength of the prepared special paper. The absence of modified magnesium borate whiskers in Comparative Example 2 results in a significant decrease in the folding endurance of the prepared special paper. The absence of polyacrylate microspheres in Comparative Example 3 results in a decrease in both the tensile strength and folding endurance of the prepared special paper. The absence of cross-linking with trans-aconitic acid in Comparative Example 4 results in a significant decrease in the wet strength retention rate of the prepared special paper.

Claims

1. A production method of special paper, characterized in that: It consists of the following steps: (1) Preparation of modified calcium titanate whiskers Mix a titanate coupling agent NDZ-201, absolute ethanol, and deionized water, add acetic acid to adjust the pH value of the reaction system to 4, stir and dissolve at 38 - 40 °C for 15 min to obtain a mixed solution, then add dry calcium titanate whiskers and stir and react at 73 - 75 °C for 1.5 h. After standing, centrifuge, wash, and dry to prepare modified calcium titanate whiskers; (2) Preparation of modified magnesium borate whiskers Mix N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute ethanol, and deionized water uniformly, then add hydrochloric acid to adjust the pH value of the system to 4.5 to obtain a mixed solution, let it stand for 5 min, hydrolyze at 38 - 40 °C for 30 min, cool to 23 - 25 °C, add magnesium borate whiskers and react for 45 min. After standing, centrifuge, wash, and dry to prepare modified magnesium borate whiskers; (3) Pulping and beating the bleached kraft pine pulp and bleached wheat straw pulp respectively to obtain the slurry of bleached kraft pine pulp and the slurry of bleached wheat straw pulp, and then mix the slurry of bleached kraft pine pulp and the slurry of bleached wheat straw pulp to prepare a mixed slurry; (4) Add acorn starch to the mixed slurry prepared in step (3) and stir and mix at room temperature, then successively add modified calcium titanate whiskers, modified magnesium borate whiskers, and polyacrylate microspheres and stir and mix, add acetic acid to adjust the pH value of the system to 5, and finally add trans-aconitic acid and stir and mix to prepare a pulp; (5) Sheet the obtained pulp on a wire, press and dry at low temperature and high temperature to prepare a special paper.

2. The production method of the special paper according to claim 1, characterized in that: In step (1), the mass ratio of the titanate coupling agent NDZ-201, absolute 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 dry calcium titanate whiskers; In step (1), the mass ratio of dry calcium titanate whiskers to the mass of the mixed solution is 1:

9.

3. The production method of the special paper according to claim 1, characterized in that: In step (1), the dry calcium titanate whiskers are obtained by vacuum drying calcium titanate whiskers at 105 °C for 3 h; In step (1), the stirring speed during the preparation of modified calcium titanate whiskers is 500 r / min; In step (1), the washing is carried out by rinsing 3 times with hot ethanol at 60 °C, and the drying is carried out by vacuum drying at 85 °C for 1.5 h.

4. The production method of the special paper according to claim 1, characterized in that: In step (2), the mass ratio of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, absolute 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 production method of the special paper according to claim 1, characterized in that: In step (2), the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane accounts for 1.35% of the mass of magnesium borate whiskers; In step (2), the washing is carried out by rinsing 3 times with ethanol at 5 °C, and the drying is carried out by vacuum drying at 40 °C for 4 h.

6. The production method of the special paper according to claim 1, characterized in that: In step (3), the mass ratio of bleached kraft pine pulp to bleached wheat straw pulp is 7 - 7.5 : 2.5 - 3; In step (3), the beating degree of the bleached kraft masson pine pulp is 38°SR, and the mass concentration of the bleached kraft masson pine pulp slurry is 20%; the beating degree of the bleached wheat straw pulp is 29°SR, and the mass concentration of the bleached wheat straw pulp slurry is 5%.

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

8. The production method of the special paper according to claim 1, characterized in that: In step (4), the mass concentration of acetic acid is 1%, after adding trans - aconitic acid, it is stirred and mixed for 10 - 12 min, and the stirring speed is 400 r / min.

9. The production method of the special paper according to claim 1, characterized in that: In step (4), the mass of the modified calcium titanate whiskers accounts for 3.5 - 4.5% of the sum of the masses of the bleached kraft 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 sum of the masses of the bleached kraft masson pine pulp and the bleached wheat straw pulp, the mass of the polyacrylate microspheres accounts for 2.5 - 3% of the sum of the masses of the bleached kraft masson pine pulp and the bleached wheat straw pulp, the mass of the acorn starch accounts for 1.6 - 1.8% of the sum of the masses of the bleached kraft 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 sum of the masses of the bleached kraft masson pine pulp and the bleached wheat straw pulp.

10. The production method of the special paper according to claim 1, characterized in that: In step (5), the pressing and drying pressure is 1.0 MPa, the temperature of low - temperature pressing and drying is 85 - 88 °C, the time of low - temperature pressing and drying is 18 - 20 s, the temperature of high - temperature pressing and drying is 153 - 155 °C, and the time of high - temperature pressing and drying is 40 - 42 s.