CN106223104B - A method of aramid fiber extrusion coating paper is prepared using PSA fiber - Google Patents

Abstract

The invention discloses a method for preparing aramid composite paper by using aryl sulfone fibers, which specifically comprises the following steps: pretreating PSA chopped fibers; deflagging the pretreated PSA chopped fibers for the first time with a deflagging machine ; then add meta-aramid pulp fiber for secondary dehydration; finally add dispersant for third decompression to obtain a suspension; inject the obtained suspension into a sheet former for dehydration forming, and press 1. Obtain an aramid composite paper base paper after drying treatment; heat press the obtained aramid composite paper base paper to obtain an aramid composite paper. The preparation method of the aramid composite paper provided by the invention can maximize the use of the high-strength properties of the chopped fibers and improve the strength performance of the meta-aramid paper.

Description

A method for preparing aramid composite paper by using arylsulfone fiber

technical field

The invention belongs to the cross technical field of papermaking industry and material industry, and relates to a method for preparing aramid fiber composite paper by using aryl sulfone fiber.

Background technique

Sheet-shaped composite material made of meta-aramid (poly-m-phenylene isophthalamide) pulp fiber and meta-aramid chopped fiber as raw materials, using modern papermaking wet papermaking technology and hot pressing , is a high-performance synthetic fiber paper-based material. Because of its tough mechanical properties, good dielectric properties, ideal high temperature resistance and flexible designability, it can be used as insulating materials, electronic materials, and structural materials in special fields such as aerospace, transportation, power, and national defense. application.

The localization of meta-aramid paper-based materials is still facing many difficulties, including the quality of raw materials, fiber dispersion and wet-laid process and equipment, especially the problem of hot-press forming process. The formed meta-aramid paper has poor mechanical strength, severe parchmentation, and poor aging resistance. Become a bottleneck restricting the further application of aramid paper.

Polysulfone fiber is polysulfone-based amide fiber, the chemical name is polyphenylsulfone terephthalamide fiber, and the English abbreviation is PSA. It is a high-performance synthetic fiber independently developed by my country with independent intellectual property rights. Its macromolecular segment structure has both para-position and meta-position structure, has a stable and regular molecular skeleton structure, high crystallinity, and good orientation. Polysulfone fiber has excellent heat resistance, chemical stability and electrical insulation, and outstanding thermal oxidation resistance. After 100 hours in hot air at 300°C, the strength retention rate is 80%, and after 50 hours in hot air at 350°C, the strength retention rate can still reach 50%, and it has good dimensional stability below 270°C . Aramid fiber has no fixed melting point, and its pyrolysis temperature is above 420°C. Even if its macromolecular chain melts, it will not crack. The chemical stability of sulfonamide fiber is outstanding, after being treated with 30% concentrated hydrochloric acid, sulfuric acid and nitric acid at 80°C, the mechanical properties of the fiber are slightly reduced. The fiber is hydrophobic fiber, which has poor dispersion effect in water. During the dispersion process of synthetic fiber pulp, it is easy to flocculate and affect the evenness and strength of paper. And in the research process of preparing high-performance synthetic fiber paper, grasping the appropriate hot-pressing process has a decisive impact on the strength of the paper. Therefore, how to improve the formation and strength of paper is the focus of research in the field of papermaking.

Contents of the invention

The purpose of the present invention is to provide a method for preparing aramid composite paper by using aramid sulfone fiber, which can maximize the use of the high-strength properties of chopped fibers and improve the strength performance of meta-aramid paper.

The technical solution adopted in the present invention is a method for preparing aramid composite paper by using sulfonamide, which specifically includes the following steps:

Step 1, pretreating the PSA chopped fibers;

In step 2, the PSA chopped fibers pretreated in step 1 are deflagged for the first time with a deflagging machine; then, meta-aramid pulp fibers are added for the second decompression; finally, the dispersant is added for the third time Dissolved to obtain a suspension;

Step 3, injecting the suspension obtained in step 2 into a paper sheet former for dehydration forming, and obtaining an aramid composite paper base paper after pressing and drying;

In step 4, the base paper of the aramid composite paper obtained in step 3 is subjected to thermocompression molding to obtain the aramid composite paper.

The present invention is also characterized in that,

The preprocessing process of step 1 is:

Soak PSA chopped fibers in a sodium dodecylbenzenesulfonate solution with a molar concentration of 1.0×10 ^-3 mol/L to 3×10 ^-3 mol/L and a temperature of 40°C to 60°C for 0.5h to 1h , and then washed 3 to 5 times with water, and finally dried in a vacuum oven at 100°C to 105°C until absolutely dry.

Wherein the mass ratio of the PSA chopped fiber to the meta-aramid pulp fiber in step 2 is 4:6.

Wherein the dispersing agent in step 2 is polyethylene oxide, and the addition amount is 0.05%～0.07% relative to the absolute dry mass of PSA chopped fiber and meta-aramid pulp fiber, and the deflaking parameter of the first deflaking is: deflaking machine 15000r～25000r for deflagging; the decompression parameters for the second decompression: 15000r～25000r for deflagging machine; 15000r～25000r for deflagging machine for the third time.

The specific process of step 3 is: inject the suspension obtained in step 2 into the paper sheet former to prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 , and then press it for 1min to 3min with an oil press to remove the wet paper sheet. Excess moisture, and finally the pressed wet paper sheet is dried in a paper dryer.

Wherein the pressure of the hydraulic press in step 3 is 0.4MPa～0.6MPa.

Wherein in step 3, the drying temperature in the paper dryer is 95° C. to 105° C., and the drying time is 5 minutes to 8 minutes.

The specific process of step 4 is as follows:

First, the aramid composite paper base paper prepared in step 3 is hot-pressed on a flat vulcanizing machine for 2 to 4 times, and then placed on a three-roller hot press for 1 to 3 times.

Wherein the hot pressing parameters on the flat vulcanizing machine in step 4 are: the hot pressing temperature is 240° C. to 290° C., the hot pressing time is 1 min to 5 min, and the hot pressing pressure is 9 MPa to 21 MPa.

Wherein the hot pressing parameters on the three-roll hot press in step 4 are: hot pressing temperature is 220° C. to 240° C., hot pressing pressure is 100 bar to 140 bar, and roll speed is 0.5 to 1.5 m/min.

The beneficial effect of the present invention is that the preparation method provided by the present invention uses PSA fiber and meta-aramid pulp fiber as raw materials, and controls the hot pressing temperature so that the temperature is lower than the melting point of the fiber, so that the surface of the PSA fiber is partially melted, and the meta-aramid fiber is partially melted. Aramid pulp fibers are melted, and under certain pressure conditions, the crystallinity of the paper is improved, and the molecular chains are arranged in a more regular order. Larger and more tightly bonded fibers, the tensile index of the paper is greatly improved. The advantage of PSA fiber-reinforced meta-aramid paper is that it can maximize the use of the high-strength properties of chopped fibers and effectively disperse them during the hot pressing process. Heat flux, thereby improving the strength properties of meta-aramid paper.

Description of drawings

Fig. 1 is the influence of the hot pressing temperature of the plate vulcanizing machine on the strength performance of the aramid fiber paper in the hot pressing process of a method for preparing aramid composite paper by using arylsulfone fiber;

Fig. 2 is the influence of the hot pressing time of the plate vulcanizing machine on the strength performance of the aramid fiber paper in the hot pressing process of a method for preparing aramid composite paper by using arylsulfone fiber;

Fig. 3 shows the influence of the hot pressing pressure of a flat vulcanizing machine on the strength performance of aramid fiber paper in the hot pressing process of a method for preparing aramid composite paper by using arylsulfone fiber according to the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The present invention adopts the method for preparing aramid fiber composite paper by using polysulfone fiber, which specifically comprises the following steps:

Step 1, pretreating the PSA chopped fibers; the pretreatment process of the PSA chopped fibers is as follows: the PSA chopped fibers are prepared at a molar concentration of 1.0×10 ^-3 mol/L to 3×10 ^-3 mol/L at a temperature of Soak in sodium dodecylbenzenesulfonate solution at 40°C to 60°C for 0.5h to 1h, then wash with water for 3 to 5 times, and finally dry in a vacuum oven at 100°C to 105°C until absolutely dry.

In step 2, the PSA chopped fibers pretreated in step 1 are deflagged for the first time with a deflagging machine; then, meta-aramid pulp fibers are added for the second decompression; finally, the dispersant is added for the third time Dissolved to obtain a suspension;

The mass ratio of PSA chopped fibers to meta-aramid pulp fibers is 4:6, the dispersant is polyethylene oxide, and the addition amount is 0.05% relative to the absolute dry mass of PSA chopped fibers and meta-aramid pulp fibers ~0.07%, the parameters of the first defrosting are: the defoliation machine is 15000r～25000r, and the concentration of defoliation is controlled at 0.3% by mass; The percentage is 0.3%; the parameters of the third deflation are: the deflation machine decompression is 15000r ~ 25000r, and the decompression concentration is controlled at 0.3% by mass.

Step 3, injecting the suspension obtained in step 2 into a paper sheet former for dehydration forming, and obtaining an aramid composite paper base paper after pressing and drying;

The specific process of step 3 is: inject the suspension obtained in step 2 into the paper sheet former to prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 , and then press it with an oil press for 1 to 3 minutes to remove excess paper in the wet sheet. moisture, and finally dry the pressed wet paper sheet in a paper dryer.

The pressure of the hydraulic press is 0.4MPa~0.6MPa, the drying temperature in the paper dryer is 95°C~105°C, and the drying time is 5min~8min;

In step 4, the aramid composite paper base paper obtained in step 3 is subjected to thermocompression molding to obtain high-performance aramid composite paper; the specific process of step 4 is:

First, heat-press the aramid composite paper base paper prepared in step 3 on a flat vulcanizing machine for 2 to 4 times, and then place it on a three-roller heat press for 1 to 3 times;

The hot pressing parameters on the flat vulcanizing machine are: the hot pressing temperature is 240°C~290°C, the hot pressing time is 1min~5min, and the hot pressing pressure is 9MPa~21MPa;

The hot-pressing parameters on the three-roller hot-pressing machine are as follows: hot-pressing temperature is 220°C-240°C, hot-pressing pressure is 100bar-140bar, and roll speed is 0.5-1.5m/min.

Example 1

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in a sodium dodecylbenzenesulfonate solution with a molar concentration of 1.0×10 ^-3 mol/L and a temperature of 40°C for 0.5h, and then washing with water for 3 times , and finally dried to absolute dryness in a vacuum oven at 100°C; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 15000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp to the deflagged PSA chopped fiber solution, and then deflake for 15000r again, and the deflammation concentration is controlled at 0.3% by mass. 0.05% of the dry mass of polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, and the flaking is 15000r, and the flaking concentration is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet forming Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.4MPa for 1min to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Drying in a dryer, the drying temperature is 95 °C, and the drying time is 5 minutes, to obtain the base paper of aramid composite paper; the obtained base paper of aramid composite paper is first hot-pressed twice on a flat vulcanizing machine, and the hot-pressing temperature is 240°C, hot-pressing time is 1min, hot-pressing pressure is 9MPa; and then placed on a three-roller hot-pressing machine for hot-pressing once, hot-pressing temperature is 220°C, hot-pressing pressure is 100bar, roll speed is 0.5m/min, High performance aramid composite paper.

Example 2

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 3.0×10 ^-3 mol/L and a temperature of 60°C for 1 hour, and then washing with water for 5 times. Finally, dry it in a vacuum oven at 105°C until it is absolutely dry; weigh 1.27g of the pretreated absolute-dry PSA chopped fibers, and disintegrate it for 25000r in a deflagging machine, and the concentration of the deflaking is controlled at 0.3% by mass, and then weigh 1.90g of absolute Dry meta-aramid pulp, add it to the deflagged PSA chopped fiber solution, and deflake it again for 25,000r, and control the deflammation concentration at 0.3% by mass, and finally dry the fibers relative to the PSA chopped fiber and meta-aramid pulp 0.07% of the mass of polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid fiber pulp, and the fluffing is 25000r, and the fluffing concentration is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper former In the process, a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 was prepared, and then pressed by a hydraulic press for 3 minutes under a pressure of 0.6MPa to remove excess water in the wet sheet, and finally the pressed wet sheet was dried on the paper Drying in a desiccator, the drying temperature is 105 ℃, and the drying time is 8min, to obtain the base paper of aramid composite paper; the obtained base paper of aramid composite paper is first hot-pressed 4 times on a flat vulcanizing machine, and the hot-pressing temperature is 290 ℃, the hot-pressing time is 5min, and the hot-pressing pressure is 21MPa; then it is placed on a three-roller hot-pressing machine and hot-pressed 3 times, the hot-pressing temperature is 240°C, the hot-pressing pressure is 140bar, and the roller speed is 1.5m/min. High performance aramid composite paper.

Example 3

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of the dry mass of polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp for 20000r, and the concentration of the defoliation is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper former In the process, a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 was prepared, and then pressed by a hydraulic press for 2 minutes under a pressure of 0.5MPa to remove excess water in the wet sheet, and finally the pressed wet sheet was dried on the paper Drying in a drier, the drying temperature is 100°C, and the drying time is 6.5min, to obtain the base paper of aramid composite paper; the obtained base paper of aramid composite paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature is 240°C, hot-pressing time is 4min, hot-pressing pressure is 18MPa; and then placed on a three-roller hot-pressing machine for hot-pressing twice, hot-pressing temperature is 230°C, hot-pressing pressure is 120bar, and the roll speed is 1m/min. Aramid composite paper with a tensile index of 23.2N·m·g ^-1 .

Example 4

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 250°C, hot pressing time is 4min, hot pressing pressure is 18MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 54.3 N·m·g ^-1 was obtained.

Example 5

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 260°C, hot-pressing time is 4min, hot-pressing pressure is 18MPa; and then placed on a three-roller hot-pressing machine for hot-pressing twice, hot-pressing temperature is 230°C, hot-pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 63.5 N·m·g ^-1 was obtained.

Example 6

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 4min, hot pressing pressure is 18MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 79.6 N·m·g ^-1 was obtained.

Example 7

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 280°C, hot-pressing time is 4min, hot-pressing pressure is 18MPa; and then placed on a three-roller hot-pressing machine for hot-pressing 2 times, hot-pressing temperature is 230°C, hot-pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 67.8 N·m·g ^-1 was obtained.

Example 8

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature The temperature is 290°C, the hot pressing time is 4min, and the hot pressing pressure is 18MPa; then it is placed on a three-roller hot pressing machine for hot pressing twice, the hot pressing temperature is 230°C, the hot pressing pressure is 120bar, and the roller speed is 1m/min. Aramid composite paper with a tensile index of 62.1N·m·g ^-1 was obtained.

During the preparation process of the aramid composite paper in the above examples 3-8, the rest of the process parameters remained unchanged, and the hot pressing temperature of the flat vulcanizer was optimized, and the optimized detection index was the determination of the tensile index, as shown in Table 1 below. In the experiment, the influence of flat vulcanizing machine on the strength properties of aramid composite paper under different hot pressing temperatures:

Table 1

The optimization results are shown in Figure 1. It can be seen from Figure 1 that when a flat vulcanizer is used for hot pressing, the tensile index of the aramid composite paper increases gradually with the increase of temperature in a certain range of temperature, and 270 °C is The optimum temperature for hot pressing of the flat vulcanizer. Since the chemical structure of the fiber and the matrix is similar, the melting point difference between the two is small, resulting in a narrow processing temperature range, and an unsuitable processing temperature will melt the fiber orientation structure and cause the proportion of the fiber in the entire material to be small , has a greater impact on the properties of the material, so the selection of hot pressing temperature is a key factor in the preparation process of aramid composite paper.

Example 9

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 1min, hot pressing pressure is 18MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 48.2 N·m·g ^-1 was obtained.

Example 10

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature The temperature is 270°C, the hot-pressing time is 2min, and the hot-pressing pressure is 18MPa; then it is placed on a three-roller hot-pressing machine for hot-pressing twice, the hot-pressing temperature is 230°C, the hot-pressing pressure is 120bar, and the roller speed is 1m/min. Aramid composite paper with a tensile index of 63.2 N·m·g ^-1 was obtained.

Example 11

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 3min, hot pressing pressure is 18MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 71.8 N·m·g ^-1 was obtained.

Example 12

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot-pressing time is 5min, hot-pressing pressure is 18MPa; and then placed on a three-roller hot-pressing machine for hot-pressing twice, hot-pressing temperature is 230°C, hot-pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 74.4N·m·g ^-1 was obtained.

During the preparation process of the aramid fiber composite paper in the above examples 6, 9, 10, 11, and 12, the rest of the process parameters remain unchanged, and the hot pressing time of the flat vulcanizer is optimized, and the optimized detection index is the determination of the tensile index , the following table 2 is the influence of flat vulcanizing machine on the strength performance of aramid paper under different hot pressing time in the optimization experiment:

Table 2

The optimized results are shown in Figure 1. It can be seen from Figure 2 that when the flat vulcanizer is used for hot pressing, the tensile index of the aramid composite paper increases gradually with the increase of time under a certain time interval, and the hot pressing At 4 minutes, the paper performance of aramid composite paper is the best.

Example 13

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 4min, hot pressing pressure is 9MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 65.8 N·m·g ^-1 was obtained.

Example 14

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 4min, hot pressing pressure is 12MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 70.3 N·m·g ^-1 was obtained.

Example 15

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 4min, hot pressing pressure is 15MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 74.6 N·m·g ^-1 was obtained.

Example 16

The PSA chopped fibers are pretreated. The pretreatment process is: soaking in sodium dodecylbenzenesulfonate solution with a molar concentration of 2.0×10 ^-3 mol/L and a temperature of 50°C for 0.75h, and then washing with water for 4 times , and finally dried in a vacuum drying oven at 102°C to absolute dryness; weighed 1.27g of pretreated absolute-dry PSA chopped fibers, and thawed 20,000r in a deflagging machine, and the deflaking concentration was controlled at 0.3% by mass, and then weighed 1.90g Add the dry meta-aramid pulp into the deflagged PSA chopped fiber solution, and deflake for 20000r again, and the deflaking concentration is controlled at 0.3% by mass. 0.06% of dry mass polyethylene oxide is added to the mixed slurry of PSA chopped fiber and meta-aramid pulp, deflagged for 20000r, and the concentration of deflagged is controlled at 0.3% by mass to obtain a suspension, which is injected into the paper sheet to form Prepare a wet sheet of aramid paper with a quantitative weight of 100g/ ^m2 in the machine, and then press it under a pressure of 0.5MPa for 2 minutes by a hydraulic press to remove excess water in the wet sheet, and finally put the wet sheet after pressing on the paper Carry out drying in the drier, drying temperature is 100 ℃, and drying time is 6.5min, obtains aramid composite paper base paper; The obtained aramid composite paper base paper is first hot-pressed on a flat vulcanizing machine for 3 times, and the hot-pressing temperature 270°C, hot pressing time is 4min, hot pressing pressure is 21MPa; and then placed on a three-roller hot pressing machine for hot pressing twice, hot pressing temperature is 230°C, hot pressing pressure is 120bar, roll speed is 1m/min, Aramid composite paper with a tensile index of 72.9 N·m·g ^-1 was obtained.

During the preparation process of the aramid composite paper in the above examples 6, 13, 14, 15, and 16, the rest of the process parameters remain unchanged, and the hot pressing pressure of the flat vulcanizer is optimized, and the optimized detection index is the determination of the tensile index , the following table 3 is the influence of the flat vulcanizing machine on the strength performance of aramid paper under different hot pressing pressures in the optimization experiment:

table 3

The optimized results are shown in Figure 3. It can be seen from Figure 3 that when using a flat vulcanizer for hot pressing, under a certain pressure range, as the pressure increases, the tensile index of the aramid composite paper increases gradually. When the pressure is 18MPa, the paper performance of aramid composite paper is the best.

From the above examples 3 to 16, it can be concluded that a flat vulcanizer is used for hot pressing, when the hot pressing temperature is 270°C, the hot pressing pressure is 18 MPa, and the hot pressing time is 4 minutes, combined with the three-roller hot pressing machine for 2 times of hot pressing, the hot pressing When the temperature is 230℃, the hot pressing pressure is 120bar, and the roll speed is 1m/min, the tensile strength of the aramid composite paper reaches the maximum, that is, 79.6N·m·g ^-1 . In the hot-pressing stage of a flat vulcanizer, under the dual effects of temperature and pressure, the actual hot-pressing temperature of the aramid composite paper is higher than the actual set temperature. The fiber has a higher degree of melting, enhanced viscous flow, and is tightly wrapped on the surface of the chopped fiber, the effective bonding area between the fibers becomes larger, the chopped fiber and pulp molecules penetrate and fuse with each other, and the reinforced phase of the chopped fiber and the pulp matrix phase The bonding performance of the phase interface formed between them is greatly improved. In the hot pressing stage of the three-roller hot press, the aramid composite paper is subjected to hot calendering, the surface strength of the paper is further improved, the surface of the paper is smoother, the uniformity is improved, and the strength performance of the paper is further improved. The strength performance of the prepared aramid composite paper is higher than that of the paper after using the three-roll hot press and the flat vulcanizer alone. Zhang index increased by 23%.

Claims (6)

1. A method for preparing aramid composite paper by using polysulfone fiber, is characterized in that: specifically comprise the following steps: Step 1, pretreating the PSA chopped fibers; In step 2, the PSA chopped fibers pretreated in step 1 are deflagged for the first time with a deflagging machine; then, meta-aramid pulp fibers are added for the second decompression; finally, the dispersant is added for the third time Dissolved to obtain a suspension; Step 3, injecting the suspension obtained in step 2 into a paper sheet former for dehydration forming, and obtaining an aramid composite paper base paper after pressing and drying; The specific process of step 3 is as follows: inject the suspension obtained in step 2 into a paper sheet former to prepare a wet sheet of aramid paper with a quantitative weight of 100 g/ ^m2 , and then press it with an oil press for 1 to 3 minutes to remove the wet sheet Finally, dry the pressed wet paper sheet in a paper dryer; Step 4, performing thermocompression molding on the aramid composite paper base paper obtained in step 3 to obtain an aramid composite paper; The concrete process of described step 4 is: First, heat-press the aramid base paper prepared in step 3 on a flat vulcanizing machine for 2 to 4 times, and then place it on a three-roller heat press for 1 to 3 times; The hot pressing parameters on the flat vulcanizing machine in the step 4 are: the hot pressing temperature is 240° C. to 290° C., the hot pressing time is 1 min to 5 min, and the hot pressing pressure is 9 MPa to 21 MPa; The hot pressing parameters on the three-roll hot press in the step 4 are: hot pressing temperature 220°C-240°C, hot pressing pressure 100bar-140bar, roll speed 0.5-1.5m/min. 2. a kind of method that adopts polysulfone fiber to prepare aramid composite paper according to claim 1, is characterized in that: the pretreatment process of described step 1 is: Soak PSA chopped fibers in a sodium dodecylbenzenesulfonate solution with a molar concentration of 1.0×10 ^-3 mol/L to 3×10 ^-3 mol/L and a temperature of 40°C to 60°C for 0.5h to 1h , and then washed 3 to 5 times with water, and finally dried in a vacuum oven at 100°C to 105°C until absolutely dry. 3. A method for preparing aramid composite paper by using sulfonamide according to claim 1, characterized in that: the mass ratio of PSA chopped fibers and meta-aramid pulp fibers in the step 2 is 4: 6. 4. a kind of method that adopts polysulfone fiber to prepare aramid fiber composite paper according to claim 3 is characterized in that: the dispersant in described step 2 is polyoxyethylene, and addition is relative to PSA chopped fiber and The absolute dry mass of meta-aramid pulp fiber is 0.05% to 0.07%. The first deflaking parameters are: deflagging machine 15000r～25000r; The defrosting parameters for the three defences are: defrosting machine defrosting 15000r ~ 25000r. 5. A method for preparing aramid composite paper by using sulfonamide according to claim 1, characterized in that: the pressure of the hydraulic press in the step 3 is 0.4MPa-0.6MPa. 6. A method for preparing aramid composite paper by using sulfonamide according to claim 1, characterized in that: in the step 3, the drying temperature in the paper dryer is 95° C. to 105° C. The drying time is 5min~8min.