CN115109407A

CN115109407A - Fiber reinforced nylon composite material and preparation method thereof

Info

Publication number: CN115109407A
Application number: CN202210897684.4A
Authority: CN
Inventors: 付金鹏; 陈勇; 何征; 吴宪; 张亮; 刘则安
Original assignee: Shenzhen Water New Material Co ltd
Current assignee: Shenzhen Water New Material Co ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2022-09-27

Abstract

The invention relates to a fiber reinforced nylon composite material and a preparation method thereof. The preparation raw materials of the fiber reinforced nylon composite material comprise the following components in parts by mass: 40 to 65 portions of nylon resin, 10 to 40 portions of long carbon fiber, 10 to 40 portions of long glass fiber and 1 to 5 portions of compatilizer, wherein the length of the long carbon fiber is 5 to 25mm, and the length of the long glass fiber is 5 to 25 mm. The fiber reinforced nylon composite material can improve the antistatic effect and reduce the cost while ensuring better mechanical property and thermal deformation temperature.

Description

Fiber reinforced nylon composite material and preparation method thereof

Technical Field

The invention relates to the field of composite materials, in particular to a fiber reinforced nylon composite material and a preparation method thereof.

Background

Polyamides (PA), commonly known as nylons, contain polar amide groups and are capable of forming hydrogen bonds. Nylon resins have excellent mechanical properties, heat resistance, electrical insulation properties, and the like, and are widely used in industry. However, nylon also has the disadvantages of poor dimensional stability, high water absorption and the like, and pure nylon resin cannot meet the performance requirements in certain application fields with high requirements on mechanical properties. The fiber reinforced nylon composite material can well improve the defects of nylon and improve the mechanical property and the heat distortion temperature of the nylon, and becomes a key research and development direction of the nylon resin reinforced modification technology in recent years. Although the mechanical property and the thermal deformation temperature of the traditional fiber reinforced nylon composite material can be improved, the problems of poor antistatic effect and high cost still exist, and the application of the traditional fiber reinforced nylon composite material in structural materials is limited.

Disclosure of Invention

Therefore, the fiber reinforced nylon composite material and the preparation method thereof are needed to be provided, wherein the fiber reinforced nylon composite material has better mechanical property and thermal deformation temperature, and meanwhile, the antistatic effect is improved and the cost is reduced.

The fiber reinforced nylon composite material comprises the following preparation raw materials in parts by weight: 40-65 parts of nylon resin, 10-40 parts of long carbon fiber, 10-40 parts of long glass fiber and 1-5 parts of compatilizer, wherein the length of the long carbon fiber is 5-25 mm, and the length of the long glass fiber is 5-25 mm.

In one embodiment, the long carbon fibers satisfy at least one of the following conditions:

(1) the long carbon fibers comprise polyacrylonitrile-based carbon fibers;

(2) the filament diameter of the long carbon fiber is 4-8 μm, and the linear density of the bundle filament is 200-2400 tex.

In one embodiment, the long glass fibers satisfy at least one of the following conditions:

(1) the long glass fiber is alkali-free glass fiber;

(2) the filament diameter of the long glass fiber is 4-8 μm, and the linear density of the bundle filament is 700-3600 tex.

In one embodiment, the nylon resin is at least one selected from nylon 6 and nylon 66, and the relative viscosity of the nylon resin is 1.8-2.8.

In one embodiment, the compatibilizer is selected from at least one of polyvinyl alcohol, maleic anhydride grafted ethylene-1-octene copolymer, maleic anhydride grafted polypropylene, and maleic anhydride grafted ethylene propylene diene monomer.

In one embodiment, the fiber reinforced nylon composite material further comprises 0.5-1 part of antioxidant by mass.

In one embodiment, the antioxidant is at least one selected from the group consisting of antioxidant 1010, antioxidant 168, antioxidant 3114, antioxidant 619, and antioxidant DSTP.

A preparation method of a fiber reinforced nylon composite material comprises the following steps:

the method comprises the following steps of (1) obtaining the following raw materials in parts by mass: 40-65 parts of nylon resin, 10-40 parts of long carbon fiber, 10-40 parts of long glass fiber and 1-5 parts of compatilizer, wherein the length of the long carbon fiber is 5-25 mm, and the length of the long glass fiber is 5-25 mm;

and mixing the raw materials to prepare the fiber reinforced nylon composite material.

In one embodiment, the step of mixing the raw materials comprises:

mixing and melting the nylon resin and the compatilizer to prepare a melt;

and (3) impregnating the long carbon fibers and the long glass fibers in the molten mass, and then drawing, cooling and pelletizing.

In one embodiment, the step of mixing the raw materials satisfies at least one of the following conditions:

(1) the temperature for mixing and melting the nylon resin and the compatilizer is 245-275 ℃;

(2) dipping the long carbon fiber and the long glass fiber in the melt, wherein the dipping temperature is 265-285 ℃;

(3) the traction speed is 8 m/min-20 m/min;

(4) the length of the granulated granules is 10 +/-2 mm.

The raw materials for preparing the fiber reinforced nylon composite material comprise a certain amount of nylon resin, long carbon fiber, long glass fiber and compatilizer. In the long fiber reinforced composite material, the fiber retention length is long, the isotropy of the fiber is good, the mechanical property of the composite material can be improved to a greater extent, and the nylon resin is reinforced in a mode of mixing the long glass fiber and the long carbon fiber, so that the antistatic effect of the composite material can be obviously improved and the cost can be reduced while the good mechanical property and the good thermal deformation temperature are ensured.

Drawings

Fig. 1 is a process flow diagram of a method for preparing a fiber reinforced nylon composite according to an embodiment.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description taken in conjunction with the accompanying drawings. The detailed description sets forth the preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In the present invention, "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

As used herein, "at least one" refers to any one, any two, or any two or more of the listed items. "at least one" means any one, any two, or any two or more of the listed items.

In this document, the technical features described in the open include the closed technical solution composed of the listed features, and also include the open technical solution including the listed features.

In this context, the temperature parameters referred to are, if not particularly limited, both for isothermal processing and for processing within a certain temperature interval. The constant temperature process allows the temperature to fluctuate within the accuracy of the instrument control.

Herein, "preferably" and the like refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The first aspect of the present invention provides a fiber reinforced nylon composite material according to an embodiment, which is prepared from the following raw materials in parts by mass: 40 to 65 portions of nylon resin, 10 to 40 portions of long carbon fiber, 10 to 40 portions of long glass fiber and 1 to 5 portions of compatilizer, wherein the length of the long carbon fiber is 5 to 25mm, and the length of the long glass fiber is 5 to 25 mm.

In some embodiments, the mass fraction of the long carbon fiber in the raw material for preparing the fiber reinforced nylon composite material is 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts or a range consisting of any two of these values. Preferably, the mass part of the long carbon fiber in the raw material for preparing the fiber reinforced nylon composite material is 15-40 parts.

In some embodiments, the long carbon fibers comprise polyacrylonitrile-based carbon fibers. The long carbon fiber has high conductivity and good antistatic effect.

In some embodiments, the long carbon fibers have a filament diameter of 4 to 8 μm and a tow linear density of 200 to 2400 tex. The long carbon fiber is easy to process and control the mass fraction, and is beneficial to linkage production.

In some embodiments, the mass fraction of the long glass fibers in the raw material for preparing the fiber reinforced nylon composite material is 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts or a range consisting of any two of these values. Preferably, the mass part of the long carbon fiber in the raw material for preparing the fiber reinforced nylon composite material is 15-40 parts.

In some embodiments, the long glass fibers are alkali-free glass fibers.

In some embodiments, the long glass fibers have a filament diameter of 4 to 8 μm and a strand density of 700 to 3600 tex. The long glass fiber is easy to process and control the quality fraction, and is beneficial to linkage production.

Although the conventional chopped fiber reinforced nylon resin has good reinforcing effect, in the process of short fiber reinforced nylon, when the fiber is mixed with the resin in an extruder, the fiber is greatly damaged due to shearing between a screw and a cylinder, the fiber length in the granules can only be maintained between 0.2mm and 1mm, and the residual length of the fiber in the obtained product is shorter. Therefore, in the embodiment, the long fiber reinforced nylon material is used, the fiber retention length is longer in the preparation process, the isotropy of the fiber is good, the mechanical property of the product can be improved to a greater extent, and the fatigue resistance of the material and the dimensional stability of the product are better. Compared with short fiber reinforced composite materials, the long fiber reinforced thermoplastic resin matrix composite material has higher mechanical properties due to the increase of the fiber retention length.

The carbon fiber has good conductivity and excellent mechanical property, can improve the performance of materials when applied to composite materials, and can improve the performance of materials when commonly used in thermosetting resin. However, the cost of the carbon fiber is high, so in this embodiment, the long glass fiber and the long carbon fiber are mixed to reinforce the thermoplastic resin, and the glass fiber which is low in price and easy to obtain is used for replacing the long carbon fiber in the premise of not affecting the product performance, thereby not only reducing the product cost, but also contributing part of the strength for the productivity of the glass fiber. The thermoplastic resin is used for replacing thermosetting resin, so that the molding processing of the product is facilitated, and the recycling and utilization of materials are facilitated.

In some embodiments, the mass part of the nylon resin in the raw material for preparing the fiber reinforced nylon composite material is in a range of 40 parts, 42 parts, 45 parts, 48 parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts or any two of these values. Preferably, the mass part of the nylon resin in the raw material for preparing the fiber reinforced nylon composite material is 40-60 parts.

In some embodiments, the nylon resin is selected from at least one of nylon 6 and nylon 66, and the relative viscosity of the nylon resin is 1.8-2.8.

In some embodiments, the compatibilizer is present in 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or a range consisting of any two of these parts, by weight, in the raw materials for preparing the fiber-reinforced nylon composite.

In some embodiments, the compatibilizer is selected from at least one of polyvinyl alcohol, maleic anhydride grafted ethylene-1-octene copolymer (MAH-g-POE), maleic anhydride grafted polypropylene (MAH-g-PP), and maleic anhydride grafted ethylene propylene diene monomer (MAH-g-EPDM). The compatilizer is added to improve the compatibility between the nylon resin and the fibers, so that the fibers can realize the effect of reinforcing the modified nylon resin.

In some embodiments, the fiber reinforced nylon composite material further comprises 0.5 to 1 part of antioxidant by mass. In a specific example, in the preparation raw material of the fiber reinforced nylon composite material, the antioxidant is in a range of 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part or any two of the above values by mass. The antioxidant is added into the fiber reinforced nylon composite material, so that the aging resistance of the material can be improved.

Specifically, the antioxidant is at least one selected from the group consisting of antioxidant 1010, antioxidant 168, antioxidant 3114, antioxidant 619 and antioxidant DSTP. It is to be understood that the antioxidant is not limited thereto, and may be other antioxidants commonly used in the art.

In some embodiments, the fiber reinforced nylon composite material is prepared from the following raw materials in parts by weight: 40 to 65 portions of nylon resin, 10 to 40 portions of long carbon fiber, 10 to 40 portions of long glass fiber, 1 to 5 portions of compatilizer and 0.5 to 1 portion of antioxidant. Furthermore, the raw materials for preparing the fiber reinforced nylon composite material comprise, by mass, 40-65 parts of nylon resin, 10-40 parts of long carbon fiber, 10-40 parts of long glass fiber, 1-5 parts of compatilizer and 0.5-1 part of antioxidant.

Preferably, the fiber reinforced nylon composite material is prepared from the following raw materials in parts by weight: 40 to 60 parts of nylon resin, 15 to 40 parts of long carbon fiber, 15 to 40 parts of long glass fiber, 1 to 5 parts of compatilizer and 0.5 to 1 part of antioxidant. Furthermore, the raw materials for preparing the fiber reinforced nylon composite material comprise, by mass, 40-60 parts of nylon resin, 15-40 parts of long carbon fiber, 15-40 parts of long glass fiber, 1-5 parts of compatilizer and 0.5-1 part of antioxidant.

In addition, the fiber reinforced composite material has good heat resistance, chemical resistance, low moisture absorption rate, excellent creep resistance and good dimensional stability of long fiber reinforced materials, and is suitable for manufacturing structures and parts in the electronic and electrical fields.

Referring to fig. 1, a second aspect of the present invention provides a method for preparing a fiber reinforced nylon composite material, including the following steps S110 and S120:

step S110: the method comprises the following steps of (1) obtaining the following raw materials in parts by mass: 40 to 65 portions of nylon resin, 10 to 40 portions of long carbon fiber, 10 to 40 portions of long glass fiber and 1 to 5 portions of compatilizer.

Wherein, the length of the long carbon fiber is 5 mm-25 mm, and the length of the long glass fiber is 5 mm-25 mm.

The specific types of the raw materials are the same as those described above, and are not described in detail herein.

Step S120: the raw materials are mixed to prepare the fiber reinforced nylon composite material.

Further, in some embodiments, the raw material further comprises 0.5 to 1 part of an antioxidant.

In some embodiments, the step of mixing the raw materials comprises:

mixing and melting nylon resin, a compatilizer and an antioxidant to prepare a melt;

the long carbon fibers and the long glass fibers are immersed in the melt, and then are pulled, cooled and cut into particles.

In some embodiments, the step of mixing the raw materials further comprises, prior to the step of: a step of drying the nylon resin in a vacuum drying oven, for example, at 110 ℃ for 6 hours.

In some embodiments, the temperature at which the nylon resin and the compatibilizer are mixed and melted is 245 ℃ to 275 ℃. For example, the temperature of the mixing and melting is 245 ℃, 250 ℃, 255 ℃, 260 ℃, 265 ℃, 270 ℃, 275 ℃ or a range consisting of any two of these values.

In some embodiments, the long carbon fibers and the long glass fibers are impregnated in the melt at a temperature of 265 ℃ to 285 ℃. For example, the impregnation temperature is 265 ℃, 270 ℃, 275 ℃, 280 ℃, 285 ℃ or a range consisting of any two of these values.

In some embodiments, the pulling speed is between 8m/min and 20 m/min. For example, the traction speed is 8mm/min, 10mm/min, 12mm/min, 15mm/min, 18mm/min, 20mm/min or a range consisting of any two of these values.

In some embodiments, the pellet length after pelletizing is 10 ± 2 mm. For example, the pellet length after dicing is 8mm, 9mm, 10mm, 11mm, 12mm or a range composed of any two of these values.

In some embodiments, the processing equipment used for the step of mixing the raw materials includes extruders, such as twin screw extruders, and impregnation dies. The dipping die is butted with an extruder port die, materials are melted and blended through the extruder, and the melt is directly extruded into a cavity of the dipping die to dip the long carbon fiber and the long glass fiber.

In one embodiment, the step of mixing the raw materials comprises: the nylon resin, the compatilizer and the antioxidant are melted and mixed in an extruder, and then the melt is extruded into a cavity of an impregnation die, so that the long carbon fiber and the long glass fiber are impregnated. After the impregnation is finished, the mixture is pulled from the impregnation die, cooled and cut into granules to obtain granules with the length of 10 +/-2 mm.

The traditional fiber reinforced nylon composite material is prepared by adopting an extrusion granulation process, the damage to fibers is large in the processing process, the fiber retention length is short, the reinforcing effect cannot be realized to the maximum extent, the conductivity of the composite material is relatively poor, and the electromagnetic shielding function of the composite material is also influenced to a certain extent, so that the application of the composite material in structural materials is limited. In the present embodiment, Long Fiber reinforced thermoplastic composites (LFTs) are mainly processed, so that the Fiber length in the composite can be retained to the maximum extent, and the maximum reinforcing efficiency can be achieved.

In some embodiments, the fiber reinforced nylon composite has a fiber length of 5mm to 25 mm.

The fiber reinforced nylon composite material prepared by the method has the special function of static electricity resistance, and simultaneously has the advantages of good heat resistance, chemical resistance, low moisture (water) absorption rate, excellent creep resistance and good dimensional stability of long fiber reinforced plastics.

In order to make the objects and advantages of the present invention more apparent, the fiber-reinforced composite material and its effects are described in further detail with reference to specific examples, it being understood that the specific examples described herein are only for the purpose of illustrating the present invention and are not to be construed as limiting the present invention. The following examples are not specifically described, and other components except inevitable impurities are not included. The examples, which are not specifically illustrated, employ drugs and equipment, all of which are conventional in the art. The experimental procedures, in which specific conditions are not indicated in the examples, were carried out according to conventional conditions, such as those described in the literature, in books, or as recommended by the manufacturer.

The following examples and comparative examples were prepared in accordance with the following product performance test methods:

notched impact strength: according to ISO 179-1 method, the specification of the test specimen is as follows: 80mm by 10mm by 4 mm.

Surface resistance: according to the method IEC 60093, samples having a diameter of 80mm and a thickness of 3mm were used.

Tensile property: the drawing speed was 5mm/min according to ISO 527.

Bending property: test speed 2mm/min according to ISO 178 method.

Example 1

The embodiment provides a preparation method of a fiber reinforced nylon composite material, which comprises the following steps:

(1) weighing the following raw materials in parts by weight: 64.5 parts of nylon resin, 10 parts of long carbon fiber, 20 parts of long glass fiber, 5 parts of compatilizer and 0.5 part of antioxidant, wherein the nylon resin is nylon 6 with the relative viscosity of 2.0, the length of the long carbon fiber is 12mm, the monofilament diameter is 4 mu m, the linear density is 2400tex, the length of the long glass fiber is 12mm, the monofilament diameter is 8 mu m, the linear density is 2400tex, the compatilizer is maleic anhydride grafted ethylene-1-octene copolymer, and the antioxidant is a mixture of the antioxidant 1010 and the antioxidant 168 with the mass ratio of 2: 3.

(2) Drying the nylon resin in a vacuum drying oven at 110 ℃ for 6 hours, and then uniformly mixing the nylon resin with a compatilizer and an antioxidant.

(3) And (3) butting the impregnation die with a mouth die of a double-screw extruder, adding the uniformly mixed material obtained in the step (2) into the double-screw extruder for melt blending, extruding the melt into a cavity of the impregnation die, and controlling the temperature of each section of a charging barrel of the extruder from one zone to the head of the extruder to 100/180/260/260/260/260/260/260/260/270 ℃.

(4) After a large amount of melt enters the cavity of the dipping die, the long carbon fiber and the long glass fiber are fully dipped in the melt under the action of tension; and drawing the material impregnated by the melt out of the impregnation die, cooling and granulating to obtain the fiber reinforced nylon composite material. Wherein the temperature of the dipping die is 280 ℃, the traction speed is 15 m/min, and the length of the granules is 12 mm.

The preparation processes of the fiber reinforced composite materials of examples 2 to 5 and comparative example 1 are similar to those of example 1, except that the raw material ratios of the fiber reinforced composite materials are different, which is specifically shown in table 1 below.

The properties of the fiber-reinforced composite materials prepared in the above examples and comparative examples are shown in the following table 1:

TABLE 1 composition and Properties of fiber reinforced Nylon composites

As can be seen from Table 1 above, in comparative example 1, no long carbon fiber is added, and the prepared composite material has no antistatic effect (it is generally considered that the surface resistance of the plastic product is 10) ¹² And a certain antistatic property is obtained when the value is less than omega). After the long carbon fiber is added, the resistance of the cable is obviously reduced to reach the level of a conductor, and the cable also has a strong shielding effect on electromagnetism. The thermoplastic resin is reinforced by adopting a mode of mixing the glass fiber and the carbon fiber, and the glass fiber which is low in price and easy to obtain is used for replacing the thermoplastic resin on the premise of not influencing the performance of a product, so that the product cost is reduced, and partial force is contributed to the capacity removal of the glass fiber.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, so as to understand the technical solutions of the present invention specifically and in detail, but not to be understood as the limitation of the protection scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. It should be understood that the technical solutions provided by the present invention, which are obtained by logical analysis, reasoning or limited experiments, are within the scope of the present invention as set forth in the appended claims. Therefore, the protection scope of the present patent shall be subject to the content of the appended claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. The fiber reinforced nylon composite material is characterized in that the fiber reinforced nylon composite material is prepared from the following raw materials in parts by mass: 40-65 parts of nylon resin, 10-40 parts of long carbon fiber, 10-40 parts of long glass fiber and 1-5 parts of compatilizer, wherein the length of the long carbon fiber is 5-25 mm, and the length of the long glass fiber is 5-25 mm.

2. The fiber reinforced nylon composite of claim 1, wherein the long carbon fibers satisfy at least one of the following conditions:

(1) the long carbon fibers comprise polyacrylonitrile-based carbon fibers;

3. The fiber reinforced nylon composite of claim 1, wherein the long glass fibers satisfy at least one of the following conditions:

(1) the long glass fiber is alkali-free glass fiber;

4. The fiber reinforced nylon composite material according to claim 1, wherein the nylon resin is at least one selected from nylon 6 and nylon 66, and the relative viscosity of the nylon resin is 1.8 to 2.8.

5. The fiber reinforced nylon composite of claim 1, wherein the compatibilizer is at least one selected from the group consisting of polyvinyl alcohol, maleic anhydride grafted ethylene-1-octene copolymer, maleic anhydride grafted polypropylene, and maleic anhydride grafted ethylene propylene diene monomer.

6. The fiber reinforced nylon composite material according to any one of claims 1 to 5, wherein the raw material for preparing the fiber reinforced nylon composite material further comprises 0.5 to 1 part of an antioxidant by mass.

7. The fiber reinforced nylon composite of claim 6, wherein the antioxidant is at least one selected from the group consisting of antioxidant 1010, antioxidant 168, antioxidant 3114, antioxidant 619, and antioxidant DSTP.

8. The preparation method of the fiber reinforced nylon composite material is characterized by comprising the following steps:

9. The method of preparing a fiber reinforced nylon composite according to claim 8, wherein the step of mixing the raw materials comprises:

mixing and melting the nylon resin and the compatilizer to prepare a melt;

10. The method of preparing a fiber reinforced nylon composite according to claim 9, wherein the step of mixing the raw materials satisfies at least one of the following conditions:

(2) dipping the long carbon fiber and the long glass fiber in the melt at 265-285 ℃;

(3) the traction speed is 8 m/min-20 m/min;

(4) the length of the granulated pellets is 10 +/-2 mm.