阅读说明：本技术 一种芳香族聚酰胺膜状沉析纤维的制备方法 (Preparation method of aromatic polyamide film-shaped fibrid ) 是由 李兰英 周万立 林志娇 何鑫业 林勇 于 2020-05-13 设计创作，主要内容包括：本发明公开了一种芳香族聚酰胺膜状沉析纤维的制备方法,属于高性能有机纤维及纸的制备领域。该方法包括以下步骤：(1)将配制好的芳香族聚酰胺溶液经过滤、计量后从带有扁平状喷丝孔的喷丝板中挤出,形成带状的聚合物溶液细流；(2)带状的聚合物溶液细流经过一段空气层后落入转速为2000～20000rpm的沉析机中与凝固浴混合,沉析1～30s,形成膜状的沉析纤维；(3)沉析纤维与凝固浴的悬浮液从沉析机出口流出后,经分离、洗涤、脱水得到沉析纤维成品。该方法简单易行,制备的沉析纤维呈完整的膜状结构,形貌统一、长度分布集中、均一性好,可用于制备出匀度和强度等性能更为优异的纸基材料。(The invention discloses a preparation method of aromatic polyamide film-shaped fibrids, belonging to the field of preparation of high-performance organic fibers and paper. The method comprises the following steps: (1) filtering and metering the prepared aromatic polyamide solution, and extruding the aromatic polyamide solution from a spinneret plate with flat spinneret orifices to form ribbon-shaped polymer solution trickle; (2) allowing the ribbon polymer solution trickle to pass through a section of air layer and then fall into a precipitation machine with the rotating speed of 2000-20000 rpm to be mixed with a coagulating bath, and precipitating for 1-30 s to form membranous precipitation fibers; (3) and (3) after the suspension of the fibrid and the coagulating bath flows out from the outlet of the precipitation machine, separating, washing and dehydrating to obtain a fibrid finished product. The method is simple and easy to implement, the prepared fibrid is of a complete film structure, uniform in appearance, concentrated in length distribution and good in uniformity, and can be used for preparing a paper-based material with more excellent uniformity, strength and other properties.)

1. The preparation method of the aromatic polyamide membrane-shaped fibrid is characterized by comprising the following steps:

(1) filtering the prepared aromatic polyamide solution, metering the aromatic polyamide solution and the coagulating bath according to the mass ratio of 1: 1-10, and extruding the aromatic polyamide solution from a spinneret plate with flat spinneret orifices to form ribbon-shaped polymer solution trickle;

(2) allowing the ribbon polymer solution trickle to pass through a section of air layer and then fall into a precipitation machine with the rotating speed of 2000-20000 rpm to be mixed with a coagulating bath, and precipitating for 1-30 s to form membranous precipitation fibers; (ii) a

(3) And (3) after the suspension of the fibrid and the coagulating bath flows out from the outlet of the precipitation machine, separating, washing and dehydrating to obtain a fibrid finished product.

2. The method for producing an aromatic polyamide film-like fibrid according to claim 1, wherein: the aromatic polyamide is obtained by polymerizing aromatic diformyl chloride and aromatic diamine, wherein:

the aromatic diformyl chloride is one or two of terephthaloyl chloride and isophthaloyl chloride; the aromatic diamine is one or more of p-phenylenediamine, m-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole, 2, 5-diaminobenzonitrile, 2, 5-dichloro-p-phenylenediamine, 2-chloro-p-phenylenediamine, 2, 6-dichloro-p-phenylenediamine, 4 '-diaminodiphenyl ether and 3, 4' -diaminodiphenyl ether.

3. The method for producing an aromatic polyamide film-like fibrid according to claim 1, wherein: in the step (1), the aromatic polyamide solution is obtained by dissolving aromatic diamine in an organic solvent containing a solubilizing salt, adding aromatic diformyl chloride, and stirring under the protection of nitrogen to react to obtain the aromatic polyamide solution with the apparent viscosity of 1000-200000 cP.

4. The method for producing an aromatic polyamide film-like fibrid according to claim 1 or 3, wherein: the solid content of the aromatic polyamide solution is 1-8%.

5. The method for producing an aromatic polyamide film-like fibrid according to claim 3, wherein: the organic solvent is one of N, N-dimethylacetamide or N-methylpyrrolidone.

6. The method for producing an aromatic polyamide film-like fibrid according to claim 3, wherein: the dissolution-assisting salt is LiCl or CaCl₂The solid content of the dissolution assisting salt in the organic solvent is 2.0-7.5%.

7. The method for producing an aromatic polyamide film-like fibrid according to claim 2, wherein: in the step (1), spinneret orifices of the spinneret plate are flat, the length of the spinneret orifices is 0.1-10 mm, and the width of the spinneret orifices is 0.05-2 mm.

8. The method for producing an aromatic polyamide film-like fibrid according to claim 1, wherein: in the step (2), the height of the air layer is 10-50 mm.

9. The method for producing an aromatic polyamide film-like fibrid according to claim 1, wherein: in the step (2), an N, N-dimethylacetamide aqueous solution with a mass concentration of 0-60% or an N-methylpyrrolidone aqueous solution with a mass concentration of 0-60% is used for the coagulation bath.

10. The method for producing an aromatic polyamide film-like fibrid according to claim 1, wherein: the fibrid is in a film shape, the average length is 0.2-3.0 mm, and the average specific surface area is 4-36 m²/g。

Technical Field

The invention relates to a preparation method of aromatic polyamide fibrid, in particular to a preparation method of membranous fibrid, belonging to the field of preparation of high-performance organic fiber and paper.

Background

At present, the high-performance paper base material is mainly meta-aramid paper and a small amount of para-aramid paper, and the aramid paper not only has excellent physical and mechanical properties, but also has better thermal stability, flame retardance, electrical insulation and radiation resistance, and is an important basic material in the fields of aviation, aerospace, national defense, electronics, communication, environmental protection, chemical engineering, ocean development and the like. The high-performance paper is mainly prepared by mixing and pulping settling fibers or pulp fibers and short-cut fibers according to a certain proportion, manufacturing paper and hot rolling, wherein the short-cut fibers are fibers obtained by cutting filaments into several millimeters; the pulp fiber is obtained by further pulping and fibrillating the chopped fiber, and the unique surface structure greatly improves the holding power and can greatly improve the strength of the paper; fibrids are a film-like fibrous material with a thickness of one to several micrometers and a length of several tens of micrometers to several millimeters. Fibrids are fibers obtained by precipitating a polymer solution by injecting a large amount of a coagulant into a strongly stirred dilute solution of the polymer or injecting the polymer solution in the form of a fine stream into a coagulating bath stirred at a high speed. The special film structure of the fibrid ensures that the fibrid has better use performance than pulp fiber in the papermaking process and has obvious advantages. For example, US20070082198a1, CN106592000A, CN108048938A, CN109321998A and the like are aramid fibrids prepared by injecting an aramid polymer solution into a coagulation bath stirred at a high speed.

It is known that the morphology of fibrids has a crucial influence on the papermaking properties. Generally, fibrids with a film-like structure have better bonding effect than fibrids or pulp fibers with a large fibrillation degree, and the prepared paper is more uniform and has better performance. In addition, the fibrids with concentrated length distribution and better uniformity can be better combined with the chopped fibers during wet papermaking, thereby being beneficial to the uniformity and the strength of the paper base material. However, the research on the form control of fibrid is less at present, and the aramid fibrid prepared by the prior art has the defects of incomplete film structure, large difference of fiber appearance, non-centralized length distribution and insufficient uniformity.

Disclosure of Invention

The invention aims to solve the technical problems and provides a preparation method of aromatic polyamide membrane-shaped fibrid, which is simple and feasible, and the prepared fibrid is in a fold-shaped film form, uniform in appearance, concentrated in length distribution and good in uniformity, and is beneficial to improving the mechanical property of a paper base material.

The purpose of the invention is realized by the following technical scheme:

a preparation method of aromatic polyamide membrane-shaped fibrids comprises the following steps:

(1) filtering the prepared aromatic polyamide solution, metering the aromatic polyamide solution and the coagulating bath according to the mass ratio of 1: 1-10, and extruding the aromatic polyamide solution from a spinneret plate with flat spinneret orifices to form ribbon-shaped polymer solution trickle;

(2) allowing the ribbon-shaped polymer solution trickle to pass through a section of air layer and then fall into a high-speed running precipitation machine to be mixed with a coagulating bath, and precipitating for 1-30 s to form membranous precipitation fibers;

in general, the size of the fibrids is related to the magnitude of the coagulation bath shear, with the greater the shear, the shorter the fibrid length, but not the shorter the better, the too short affects the papermaking process and sheet properties. The rotating speed of the settling machine is 2000-20000 rpm, preferably 4000-10000 rpm, and more preferably 6000-8000 rpm. The rotational speed of the precipitation machine is the shear rate of the coagulation bath.

(3) And (3) after the suspension of the fibrid and the coagulating bath flows out from the outlet of the precipitation machine, separating, washing and dehydrating to obtain a fibrid finished product.

In the present invention, the aromatic polyamide is obtained by polymerizing aromatic dicarboxylic acid chloride and aromatic diamine, wherein:

the aromatic diformyl chloride is one or two of terephthaloyl chloride and isophthaloyl chloride;

the aromatic diamine is one or more of p-phenylenediamine, m-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole, 2, 5-diaminobenzonitrile, 2, 5-dichloro-p-phenylenediamine, 2-chloro-p-phenylenediamine, 2, 6-dichloro-p-phenylenediamine, 4 '-diaminodiphenyl ether and 3, 4' -diaminodiphenyl ether.

In the step (1), the aromatic polyamide solution is prepared by dissolving aromatic diamine in an organic solvent containing solubilizing salt, adding aromatic diacid chloride, and stirring under the protection of nitrogen to react to obtain the aromatic polyamide solution with the apparent viscosity of 1000-200000 cP at room temperature, wherein the aromatic polyamide solution with the apparent viscosity of 5000-50000 cP is preferable. It is known that the apparent viscosity of a polymer solution is related to factors such as molecular weight, solid content, temperature and the like, and if the apparent viscosity is too low, the molecular weight of the polymer is low, the prepared fibrid is in a fine powder shape, the length-diameter ratio is too small, the papermaking adaptability is poor, and the tensile strength and the tearing strength of paper which cannot be made or is prepared are too low; if the apparent viscosity is too high, the difficulty of transporting and molding the polymer solution is increased.

The solid content of the aromatic polyamide solution is 1-8%, the polymer solution is poor in flowability due to the fact that the solid content is too high, the polymer solution is not easy to process, and the production efficiency is affected due to the fact that the solid content is too low.

Further, the organic solvent is one of N, N-dimethylacetamide or N-methylpyrrolidone; the dissolution-assisting salt is LiCl or CaCl₂But from the perspective of fluxing salt recovery and waste liquid treatmentIt is preferable to use a single component solubilizing salt.

The solid content of the dissolution assisting salt in the organic solvent is 2.0-7.5%.

In the step (1), the spinneret plate used in the invention has flat spinneret holes, the length of the spinneret holes is 0.1-10 mm, and the width of the spinneret holes is 0.05-2 mm.

In the step (2), the height of the air layer is 10-50 mm. The height of the air layer is too low, and the coagulating bath is easy to splash to the surface of the spinneret plate in the high-speed stirring process, so that the spinneret plate blocks holes; and the air layer is too high, the strip-shaped solution trickles are gradually changed into round linear solution trickles due to the action of internal stress in the falling process, and the pre-forming effect is lost.

In the step (2), the coagulation bath adopted by the invention is one of N, N-dimethylacetamide aqueous solution with the mass concentration of 0-60% or N-methylpyrrolidone aqueous solution with the mass concentration of 0-60%. The concentration of the coagulation bath is important to influence the morphology of the precipitated fiber, the lower the concentration is, the more violent the coagulation is, and the ribbon-shaped solution trickles are separated out immediately after entering the coagulation bath to form a film-shaped morphology. The concentration of the coagulating bath is 0-60%, preferably 10-30%.

The fibrid prepared by the method is film-shaped, the average length is 0.2-3.0 mm, and the average specific surface area is 4-36 m²/g。

Compared with the prior art, the invention has the following beneficial effects:

(1) in the prior art, a spinneret plate is not added in the process of preparing fibrid, polymer solution trickles flow into a strand and flows into a coagulating bath, the fiber morphology is not easy to control, and the prepared fibrid has non-uniform morphology and contains components with high fibrillation degree and large length-diameter ratio. According to the invention, the polymer solution flows out of the spinneret plate with the flat spinneret orifice and passes through a section of air layer, so that the polymer solution trickle forms a strip-shaped solution trickle before entering the coagulating bath, and the strip-shaped solution trickle is further stretched and deformed into the fibrid with a film-shaped structure under the strong shearing action of the coagulating bath, thereby solving the defects of incomplete film-shaped structure, large fiber morphology difference, non-centralized length distribution and insufficient uniformity of the aramid fibrid prepared by the prior art.

The invention firstly measures the prepared aromatic polyamide solution and extrudes the solution from a spinneret plate with flat spinneret orifices, the formed flat/ribbon-shaped solution trickle falls into a coagulating bath in a high-speed shearing precipitation device after passing through a section of air layer, and the flat/ribbon-shaped trickle is further stretched and deformed into a film shape under the strong shearing action of the coagulating bath. At the same time of the stretching deformation, a double diffusion effect occurs, and the film-shaped solution is converted into solid film-shaped fibrids in a thin flow mode. And (4) separating, washing and dehydrating the fibrid dispersion liquid flowing out of the settling equipment to obtain a finished product. The fibrid prepared by the method is of a complete film structure, the size and the specific surface area of the fibrid can be accurately controlled by adjusting the process parameters, the size distribution of the fibrid is concentrated, the uniformity is good, and the mechanical property of the paper base material is favorably improved.

(2) According to the invention, the height of the air layer is set to be 10-50 mm, so that the phenomenon that the coagulating bath is easy to splash to the surface of a spinneret plate in the high-speed stirring process to cause hole blockage of the spinneret plate due to too low height of the air layer can be avoided; and the solution trickles in the falling process are not changed from a belt shape to a circular line shape due to the over-high height of the air layer, so that the pre-forming effect is not lost.

(3) The fibrid prepared by using the spinneret plate with the spinneret orifice length of 0.1-10 mm and the width of 0.05-2 mm has a uniform structure, is film-shaped, has concentrated length distribution, and can be used for preparing a paper-based material with more excellent properties such as uniformity, strength and the like.

Drawings

FIG. 1 is a schematic view of a spinneret plate with flat spinneret orifices

Wherein, 1-spinneret plate and 2-spinneret hole.

Fig. 2 is an electron micrograph of the fibrids prepared in example 1.

Fig. 3 is an electron micrograph of a fibrid prepared in comparative example.

Detailed Description

The present invention is described in detail by the following examples, which should be construed as limiting the scope of the invention and the insubstantial modifications and adaptations of the invention by those skilled in the art based on the teachings herein are intended to be covered by the following examples.

Description of the drawings: the morphology, properties and length distribution of the fibrids produced by the following examples and comparative examples are detailed in tables 1-8, according to the following experimental methods and criteria:

1) the average length and the distribution of the fibrid are measured by a fiber analyzer according to the measurement of the length of the paper pulp fiber of GB/T29779-2013, namely a non-polarized light method;

2) the average specific surface area of the fibrid is measured by adopting a specific surface area tester and measuring the specific surface area of the solid substance according to the national standard GB/T19587-2004 gas adsorption BET method;

3) the apparent morphology of the fibrids was obtained by observation with an optical microscope and an electron microscope (SEM).

Example 1

The preparation method comprises the steps of copolymerizing p-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole and terephthaloyl chloride in an N, N-dimethylacetamide/LiCl solvent system (LiCl solid content is 2.0%) according to a molar ratio of 3:7:10 to obtain a polymer solution with the concentration of 4% and the apparent viscosity of 30000cP, filtering, metering according to a mass ratio of the polymer solution to a coagulating bath (water) of 1:1, extruding the polymer solution from a spinneret plate with a spinneret orifice specification of 0.1mm multiplied by 2mm, enabling the formed solution trickle to pass through an air layer with the height of 20mm, entering a settling machine with the rotating speed of 8000rpm, mixing with water, dispersing and carrying out coagulation forming on the solution trickle in water to obtain a mixed solution of settled fibers and the water, wherein the settling time is 3 s. And the mixed solution flows out of an outlet of the settling machine and then enters centrifugal equipment, and settled fibers are obtained after separation and washing. The morphology, properties and length distribution of the fibers are shown in table 1, table 2 and figure 1.

Table 2 example 1 length distribution of fibrids

Example 2

Copolymerizing p-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole and isophthaloyl dichloride in an N, N-dimethylacetamide/LiCl solvent system (LiCl solid content is 3.5%) according to a molar ratio of 5:5:10 to obtain a polymer solution with the concentration of 5% and the apparent viscosity of 8000cP, filtering, metering according to a mass ratio of the polymer solution to a coagulation bath (N, N-dimethylacetamide aqueous solution with the concentration of 60%) of 1:7, extruding from a spinneret plate with the specification of 0.05mm multiplied by 5mm, passing the formed solution trickle through an air layer with the height of 50mm, mixing with the N, N-dimethylacetamide aqueous solution with the concentration of 60% in a precipitation machine with the rotation speed of 6000rpm, dispersing and coagulating to obtain a mixed solution of precipitation fibers and the coagulation bath after the solution trickle is subjected to coagulation forming in the coagulation bath, the settling time was 10 s. And the mixed solution flows out of an outlet of the settling machine and then enters centrifugal equipment, and settled fibers are obtained after separation and washing. The morphology, properties and length distribution of the fibers are shown in tables 1 and 3.

Table 3 example 2 length distribution of fibrids

Example 3

P-phenylenediamine and p-phthaloyl chloride are mixed in N-methylpyrrolidone/CaCl according to the molar ratio of 1:0.98₂Solvent system (CaCl)₂Solid content is 7.5 percent), the polymer solution with concentration of 8 percent and apparent viscosity of 4000cP is obtained by copolymerization, the filtration treatment is carried out, the polymer solution and the coagulating bath (N-methyl pyrrolidone aqueous solution with concentration of 30 percent) are metered according to the mass ratio of 1:5, the polymer solution and the coagulating bath are extruded from a spinneret plate with the specification of 0.1mm multiplied by 2mm, the formed solution trickle passes through an air layer with the height of 20mm and enters a precipitation machine with the rotating speed of 2000rpm to be mixed with the N-methyl pyrrolidone aqueous solution with the concentration of 30 percent, the solution trickle is dispersed and coagulated and formed in the coagulating bath to obtain the mixed solution of precipitated fiber and the coagulating bath, and the precipitation time is 10 s. Precipitating the mixed solutionAnd (4) after flowing out of the machine outlet, feeding into a centrifugal device, and separating and washing to obtain the fibrid. The morphology, properties and length distribution of the fibers are shown in tables 1 and 4.

Table 4 example 3 length distribution of fibrids

Example 4

P-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole, 2-chloro-p-phenylenediamine and terephthaloyl chloride are copolymerized in an N, N-dimethylacetamide/LiCl solvent system (LiCl solid content is 3.0%) according to a molar ratio of 3:6:1:10 to obtain a polymer solution with a concentration of 6% and an apparent viscosity of 100000cP, the polymer solution is filtered, metered according to a mass ratio of 1:10 of the polymer solution to a coagulation bath (N, N-dimethylacetamide aqueous solution with a concentration of 15%), the polymer solution is extruded from a spinneret plate with a spinneret orifice specification of 0.2mm multiplied by 10mm, the formed solution fine flow passes through an air layer with the height of 10mm and enters a precipitation machine with the rotation speed of 2000rpm to be mixed with the N, N-dimethylacetamide aqueous solution with the concentration of 15%, and the solution fine flow is dispersed in the coagulation bath, And (3) obtaining a mixed solution of the precipitation fiber and the coagulation bath after coagulation forming, wherein the precipitation time is 30 s. And the mixed solution flows out of an outlet of the settling machine and then enters centrifugal equipment, and settled fibers are obtained after separation and washing. The morphology, properties and length distribution of the fibers are shown in tables 1 and 5.

Table 5 example 4 length distribution of fibrids

Example 5

P-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole, 4' -diaminodiphenyl ether and terephthaloyl chloride are copolymerized in an N, N-dimethylacetamide/LiCl solvent system (LiCl solid content is 3.5%) according to a molar ratio of 2:6:2:10 to obtain a polymer solution with a concentration of 1% and an apparent viscosity of 1000cP, the polymer solution is filtered, metered according to a mass ratio of the polymer solution to a coagulation bath (N, N-dimethylacetamide aqueous solution with a concentration of 15%) and then extruded from a spinneret with a spinneret orifice specification of 0.2mm x 10mm, the formed solution stream passes through an air layer with a height of 10mm and then enters a precipitation machine with a rotation speed of 20000rpm to be mixed with the N, N-dimethylacetamide aqueous solution with a concentration of 15%, and the solution stream passes through a dispersion and a dispersion device in the coagulation bath, And (3) obtaining a mixed solution of the precipitation fiber and the coagulation bath after coagulation forming, wherein the precipitation time is 1 s. And the mixed solution flows out of an outlet of the settling machine and then enters centrifugal equipment, and settled fibers are obtained after separation and washing. The fiber properties are shown in tables 1 and 6.

Table 6 example 5 length distribution of fibrids

Example 6

P-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole, 4' -diaminodiphenyl ether, 2, 5-diaminobenzonitrile and terephthaloyl chloride are mixed in a molar ratio of 2:6:1:1:10 in N-methylpyrrolidone/CaCl₂（CaCl₂Solid content is 6.0%), copolymerizing to obtain a polymer solution with concentration of 8% and apparent viscosity of 200000cP, filtering, extruding from a spinneret plate with spinneret orifice specification of 1mm multiplied by 10mm after metering according to the mass ratio of the polymer solution to a coagulating bath (N-methyl pyrrolidone aqueous solution with concentration of 5%) to form a solution stream, passing through an air layer with the height of 40mm, mixing with N-methyl pyrrolidone aqueous solution with concentration of 5% in a precipitation machine with the rotation speed of 10000rpm, dispersing and solidifying the solution stream in the coagulating bath to obtain a mixed solution of precipitated fibers and the coagulating bath, wherein the precipitation time is 20 s. And the mixed solution flows out of an outlet of the settling machine and then enters centrifugal equipment, and settled fibers are obtained after separation and washing. The morphology, properties and length distribution of the fibers are shown in tables 1 and 7.

Table 7 example 6 length distribution of fibrids

Comparative example

This comparative example is a comparative example to example 1.

The preparation method comprises the steps of copolymerizing p-phenylenediamine, 2- (4-aminophenyl) -5-aminobenzimidazole and terephthaloyl chloride in an N, N-dimethylacetamide/LiCl solvent system (LiCl solid content is 2.5%) according to a molar ratio of 3:7:10 to obtain a 4% polymer solution, filtering, metering according to a mass ratio of the polymer solution to a coagulating bath (water) of 1:7, performing in a non-spinneret plate, directly pumping the polymer solution into a settling machine with a rotation speed of 8000rpm to mix with water in a strand-shaped trickle flow mode, dispersing the solution trickle flow in the water, solidifying and forming to obtain a mixed solution of settled fibers and the water, wherein the settling time is 3 s. And the mixed solution flows out of an outlet of the settling machine and then enters centrifugal equipment, and settled fibers are obtained after separation and washing. The morphology, properties and length distribution of the fibers are shown in table 1, table 8 and figure 3.

Table 8 length distribution of comparative example fibrids

1. As can be seen from the morphology of the fibrids in table 1, the fibrids obtained by extruding the aramid solutions of examples 1 to 6 through a spinneret having flat spinneret holes are film-shaped, and are not preformed by the spinneret, and the fibrids are mainly film-shaped but have more fine fibers and have inconsistent and non-uniform morphology, by using the comparative example in which the aramid solutions are directly fed into a high-speed precipitation machine as a strand.

2. As can be seen from tables 2 to 8, the fibrids of examples 1 to 6 had a length distribution of 70% or more concentrated in a certain range and had good uniformity, while the fibrids of comparative examples had a length distribution of only 56.7% concentrated in a certain range, had a relatively dispersed length distribution and had poor uniformity.

3. As can also be seen from fig. 2 and 3, the fibrids of example 1 are complete film-like structures, and the fibrids of the comparative example are in a curled cord shape, and have larger morphology difference and more fine fibers.

The analysis further shows that the fibrid prepared by the invention has uniform and film-shaped structure, uniform and concentrated length distribution and better apparent morphology, and can be used for preparing paper-based materials with more excellent properties such as uniformity, strength and the like.