CN113021936A

CN113021936A - Continuous molding device and molding method for thermoplastic composite material sandwich structure

Info

Publication number: CN113021936A
Application number: CN202110255331.XA
Authority: CN
Inventors: 张守玉; 杨杰; 王孝军; 陈同海; 水锋
Original assignee: Nanjing Tesu Composite Material Co ltd
Current assignee: Nanjing Tesu Composite Material Co ltd
Priority date: 2021-03-09
Filing date: 2021-03-09
Publication date: 2021-06-25

Abstract

The invention discloses a continuous forming device for a thermoplastic composite sandwich structure, which comprises an upper skin pretreatment device, a lower skin pretreatment device, a core layer pretreatment device, an upper skin dipping die, a lower skin dipping die, a core layer forming device, a core layer transmission device, a sandwich forming roller and a double-steel belt press. A continuous forming process for the thermoplastic composite sandwich structure is also disclosed. The invention directly prepares the fiber raw material and the resin matrix raw material into a finished product through a set of equipment, compared with the existing interlayer mechanism, the manufacturing difficulty is low, the manufacturing efficiency is greatly improved, the invention can be used for continuous, batch and industrial production, and the prepared thermoplastic composite material has the advantages of improved interlayer structure strength and better performances of compression resistance, bending resistance, delamination resistance and the like.

Description

Continuous molding device and molding method for thermoplastic composite material sandwich structure

Technical Field

The invention belongs to the field of interlayer composite materials, and particularly relates to a continuous molding device and a molding method for a thermoplastic composite material interlayer structure.

Background

The use of low-density sandwich structure materials in sandwich structure composite materials can increase the thickness of the laminated plate and greatly improve the rigidity of the laminated plate, so that the composite materials with the structure of the type are widely applied to the fields of aerospace, ship manufacturing, military industry and the like. At present, the types of sandwich structure materials are mainly rigid foam, honeycomb, balsa wood and corrugated structures; although the sandwich structure material has been used in various fields as a sandwich material, the extension of the application field is limited due to the structural defects thereof.

CN105172280B discloses a honeycomb sandwich panel composite material, which comprises an upper skin, an upper surface adhesive, a honeycomb sandwich, a lower surface adhesive and a lower skin from top to bottom in sequence, wherein the bonding property of the honeycomb sandwich layer and a panel is weak and needs waterproof treatment.

CN202010161728 discloses a-wave lattice web reinforced composite sandwich structure and a preparation method thereof, comprising a core material, a wave lattice web and fiber panel layers, wherein the upper and lower surfaces of the core material are wrapped with fiber cloth and cured with resin to form the fiber panel layers. The core layer of the structure has large thickness and heavy weight.

CN201820843247 discloses a cavity composite material sandwich board capable of burying pipelines, which comprises an upper panel and a lower panel, wherein a plurality of pipes with trapezoidal cross sections are arranged between the upper panel and the lower panel, and the upper panel, the lower panel and the pipes are all made of fiber reinforced composite materials. The plurality of trapezoidal pipes in the structure are not connected into a whole, so that the manufacturing difficulty is high.

CN201110231438 discloses a dot matrix sandwich panel made of a composite material, wherein a core of the dot matrix sandwich panel is composed of a plurality of embedded strip groups, each embedded strip group comprises a first embedded strip and a second embedded strip, the first embedded strip and the second embedded strip are clamped, splicing difficulty is high, and manufacturing efficiency is low.

Disclosure of Invention

The invention aims to provide a continuous forming device and a forming method of a thermoplastic composite material sandwich structure, which can manufacture a core layer and the sandwich structure into a product at one time by one set of equipment, are very convenient to manufacture, can realize continuous manufacturing and have high efficiency.

The purpose of the invention is realized as follows: the continuous forming device for the thermoplastic composite material sandwich structure comprises an upper skin pretreatment device, a lower skin pretreatment device, a core layer pretreatment device, an upper skin dipping die, a lower skin dipping die, a core layer shaping device, a core layer transmission device, a sandwich forming roller and a double-steel belt press;

the sandwich layer pre-treatment device, the sandwich layer dipping die, the sandwich layer shaping device, the sandwich layer forming roller and the double-steel belt press are sequentially arranged, the sandwich layer shaping device comprises a group of hot-pressing shaping rollers and a group of cold-pressing shaping rollers, uniform shaping teeth are arranged on the outer walls of the hot-pressing shaping rollers and the cold-pressing shaping rollers, the length direction of the shaping teeth is the axial direction of the hot-pressing shaping rollers and the cold-pressing shaping rollers, and the section of the shaping teeth is trapezoidal;

the upper skin pretreatment device is connected with the upper skin dipping die, the lower skin pretreatment device is connected with the lower skin dipping die, and the upper skin dipping die and the lower skin dipping die are respectively positioned above and below the core layer transmission device.

Furthermore, the upper skin pretreatment device, the lower skin pretreatment device and the core layer pretreatment device are the same and respectively comprise a creel, a fiber pre-tightening device and a yarn spreading device which are sequentially arranged.

Further, a fiber width-fixing roller is arranged between the yarn spreading device and the core layer dipping die.

Further, a first preheating device is arranged between the fiber pre-tightening device and the yarn spreading device.

Further, the upper skin dipping die, the lower skin dipping die and the core layer dipping die are all connected with an extruder.

Furthermore, an upper guide roller is arranged between the upper skin dipping die and the interlayer forming roller, and a lower guide roller is arranged between the lower skin dipping die and the interlayer forming roller.

And second preheating devices are arranged between the upper skin dipping die and the interlayer forming roller and between the lower skin dipping die and the interlayer forming roller.

Further, still include the cutting machine, intermediate layer forming roll, two steel belt presses and cutting machine set gradually.

The sandwich structure forming method of the continuous forming device for the thermoplastic composite sandwich structure comprises the steps of introducing molten resin matrix into a core layer dipping die, an upper skin dipping die and a lower skin dipping die, respectively pretreating core layer fibers, upper skin fibers and lower skin fibers by a core layer pretreatment device, an upper skin pretreatment device and a lower skin pretreatment device, then enabling the core layer fibers to enter the core layer dipping die, enabling the upper skin fibers to enter the upper skin dipping die, enabling the lower skin fibers to enter the lower skin dipping die, dipping the resin matrix to form an upper skin, a planar core layer and a lower skin, sequentially extruding the planar core layer by a hot-pressing sizing roller and a cold-pressing sizing roller to obtain the trapezoidal-wave-shaped core layer structure, conveying the core layer structure to a sandwich layer forming roller by a core layer conveying device, and pressing and fixing the upper skin on the upper surface of the core layer structure by the sandwich layer forming roller, and pressing and fixing the lower skin on the lower surface of the sandwich layer structure to obtain a sandwich structure, and finally cooling and shaping the sandwich structure by using a double-steel belt press.

Further, the pretreatment comprises the steps of unreeling, pre-tightening and fiber unfolding of the fiber raw materials in sequence.

Further, after the fiber raw material is pre-tightened, the fiber raw material is preheated to 80-300 ℃ by using a first preheating device.

Further, after impregnation, the upper skin, the planar core layer and the lower skin have a thickness in the range of 0.1-2mm and a width in the range of 8-1000 mm.

Further, the core layer fiber, the upper skin fiber and the lower skin fiber are one or a mixture of several of carbon fiber, glass fiber, aramid fiber and basalt fiber.

Further, the resin matrix is one of PP, PE, PA, PPS and PEEK plastics.

Further, the hot-pressing temperature of the hot-pressing sizing roller is 10-50 ℃ lower than the melting point of the resin matrix, and the cold-pressing temperature of the cold-pressing sizing roller is 50-100 ℃.

Further, the upper skin and the lower skin were preheated to 200-.

The invention has the beneficial effects that: 1. the sandwich structure of the invention has light weight, is reinforced by adopting fibers, has improved strength and better compression resistance, bending resistance and the like. 2. Anti-delamination: go up covering, covering and sandwich layer structure and be same material and provide Z to the fibre reinforcement, more traditional sandwich structure combined material has stronger anti layering ability. 3. The product form is diversified: the reinforcement can be one or a mixture of several of carbon fiber, glass fiber, aramid fiber and basalt fiber, the resin matrix can adopt polypropylene, polyethylene, nylon, polyphenylene sulfide, polyether ether ketone and the like, and the diversification of product forms is realized; the corrugated structure of the invention can be used under different working conditions. 4. The internal stress of the core layer structure material is uniformly released under the action of a hot-cold setting roller. 5. Compared with the existing interlayer mechanism, the manufacturing difficulty is low, the manufacturing efficiency is greatly improved, and the method can be used for continuous, batch and industrial production.

Drawings

FIG. 1 is a schematic representation of a sandwich structure of the present invention;

FIG. 2 is a schematic cross-sectional view of a core structure;

FIG. 3 is a schematic view of a production apparatus of the present invention;

FIG. 4 is a schematic illustration of a hot press sizing roll and a cold press sizing roll of the present invention;

FIG. 5 is a schematic top view of the upper skin impregnation die, lower skin impregnation die, and core layer impregnation die of the present invention;

reference numerals: 1, a creel; 2-fiber pre-tightening device; 3-a first preheating device; 4, a yarn spreading device; 5, fiber width fixing roller; 6, dipping the core layer in a mould; 7-hot pressing sizing roller; 8, cold pressing and shaping roller; 9-core layer structure; 10-core layer transmission device; 11-upper skin dipping die; 12-an upper guide roll; 13-interlayer forming roller; 14-double steel belt press; 15-a cutting machine; 16-lower guide roll; 17-lower skin dipping die; 20-shaping teeth; 30-an extruder; 40-a second preheating device; 100-core fibers; 110-upper skin fiber; 120-lower skin fiber; 130-upper skin; 140-lower skin; 200-resin matrix.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

As shown in fig. 1, the sandwich structure of the thermoplastic composite material of the present invention includes an upper skin 130, a core structure 9 and a lower skin 140, wherein the core structure 9 has a continuous trapezoidal waveform, which has higher mechanical properties such as rigidity than the conventional core materials (balsa wood, honeycomb, foam, etc.), and in addition, the compression resistance and bending resistance are improved by arranging the reinforcing fibers in the "Z" direction.

As shown in fig. 2, the core structure 9 includes core fibers 100 and a resin matrix 200, and the resin matrix 200 covers the core fibers 100. Similarly, the upper skin 130 and the lower skin 140 also include internal fibers and a fiber-coated resin matrix 200, and by providing the reinforcing fibers, the rigidity of the upper skin 130, the core structure 9, and the lower skin 140 can be improved, so that the bending resistance, the compression resistance, and the like of the sandwich structure can be enhanced. In addition, because the materials and the structures of the upper skin 130, the core structure 9 and the lower skin 140 are consistent, the composite material has stronger anti-delamination capability compared with the traditional sandwich structure composite material.

The continuous molding device for the thermoplastic composite sandwich structure comprises an upper skin pretreatment device, a lower skin pretreatment device, a core layer pretreatment device, an upper skin dipping die 11, a lower skin dipping die 17, a core layer dipping die 6, a core layer shaping device, a core layer transmission device 10, a sandwich molding roller 13 and a double-steel belt press 14, as shown in fig. 3.

Sandwich layer preprocessing device, sandwich layer dipping die 6, sandwich layer setting device, intermediate layer forming roll 13 and two steel belt press 14 set gradually, sandwich layer setting device includes a set of hot pressing stock roll 7 and a set of stock roll 8 of colding pressing, the outer wall of hot pressing stock roll 7 and the stock roll 8 of colding pressing all is provided with even design tooth 20, the length direction of design tooth 20 is hot pressing stock roll 7 and the axial of the stock roll 8 of colding pressing, and the section of design tooth 20 is trapezoidal.

The upper skin pretreatment device is connected with the upper skin dipping die 11, the lower skin pretreatment device is connected with the lower skin dipping die 17, and the upper skin dipping die 11 and the lower skin dipping die 17 are respectively positioned above and below the core layer transmission device 10.

Go up covering preprocessing device, sandwich layer preprocessing device and be used for respectively carrying out the preliminary treatment to last covering fibre 110, covering fibre 120 and sandwich layer fibre 100 down, it is the same to go up covering preprocessing device, covering preprocessing device and sandwich layer preprocessing device down, and all including creel 1, fibre preloading device 2, the exhibition yarn device 4 that sets gradually.

The creel 1 is used for unreeling fiber raw materials, the fiber raw materials are one or a mixture of several of carbon fibers, glass fibers, aramid fibers and basalt fibers, and the automatic unreeling machine is mounted on the creel 1 and can unreel according to the comprehensive requirements of production speed and fiber tension.

The fiber pre-tightening device 2 is used for applying a certain tension to the fiber to initialize a fiber path, and generally comprises a plurality of pre-tightening shafts, and the pre-tightening force to the fiber is adjusted by adjusting the heights of the pre-tightening shafts.

The yarn spreading device 4 is used for spreading fibers, and the existing equipment such as airflow yarn spreading equipment and the like is adopted, so that the abrasion-free spreading of the fiber bundles can be realized.

A fiber width-fixing roller 5 is arranged between the yarn spreading device 4 and the core layer dipping die 6, and the fiber width-fixing roller 5 is used for controlling the width of the fibers, so that the width of the fibers is kept stable, and the uniformity of fiber distribution is improved.

A first preheating device 3 is arranged between the fiber pre-tightening device 2 and the yarn spreading device 4, the first preheating device 3 preheats the fiber 1 and can remove moisture and sizing agent on the surface of the fiber, and the preheating temperature range is 80-300 ℃, and is preferably 150 ℃. The preheating device 3 can be an existing electric heating device or the like, and an infrared preheating device is preferably adopted in the invention.

The upper skin impregnation die 11, the lower skin impregnation die 17 and the core layer impregnation die 6 are respectively used for impregnating the upper skin fiber 110, the lower skin fiber 120 and the core layer fiber 100, and coating the resin matrix 200 on the fiber surface. The upper skin impregnation die 11, the lower skin impregnation die 17 and the core layer impregnation die 6 are filled with a molten resin matrix 200, one end of each die is provided with a fiber inlet, the other end of each die is provided with a fiber outlet, and the fibers are impregnated in the resin matrix 200 when passing through the impregnation dies, so that the resin matrix 200 covers the fibers 100. In order to supplement the impregnation die with the resin matrix 200, an extruder 30 is connected to each of the upper skin impregnation die 11, the lower skin impregnation die 17, and the core layer impregnation die 6 as shown in fig. 5. The extruder 30 can plasticize the resin matrix raw material, and extrude the plasticized resin matrix 200 into an impregnation die, thereby continuously providing the resin matrix 200 and realizing continuous production. The extruder 30 may be a conventional twin-screw or single-screw extruder. The stretched fiber bundle is impregnated with monofilaments in an impregnation die; then shaping by a mouth die and extruding; the prepared prepreg has the thickness range of 0.1-2mm and the width of 8-300 mm.

After the core layer dipping die 6, the core layer is a plane type, the shaping device is used for shaping the planar core layer into a trapezoidal waveform, a single hot-pressing shaping roller 7 and a single cold-pressing shaping roller 8 are shown in fig. 4, the hot-pressing shaping roller 7 and the cold-pressing shaping roller 8 are both two, the shaping teeth 20 of the two hot-pressing shaping rollers 7 are mutually meshed, the shaping teeth 20 of the two cold-pressing shaping rollers 8 are mutually meshed, and the trapezoidal shaping teeth 20 are utilized for extruding the planar core layer, so that the core layer is deformed. The hot-pressing sizing roller 7 and the cold-pressing sizing roller 8 are identical in size and structure, and the diameter range of the sizing rollers is 100-200mm (preferably 150 mm). Firstly, a hot-pressing shaping roller 7 is used for extrusion shaping, and then a cold-pressing shaping roller 8 is used for extrusion shaping, wherein the temperature range of the hot-pressing shaping roller 7 is 10-50 ℃ lower than the melting point of the resin matrix (preferably 20 ℃ lower), and the temperature range of the cold-pressing shaping roller 8 is 50-100 ℃ (preferably 80 ℃).

The sandwich forming roll 13 is used to press together the upper skin 130, the core structure 9 and the lower skin 140 to form a sandwich structure. The sandwich forming roll 13 comprises two press rolls, the two press rolls have a proper distance therebetween, the distance is determined according to the thickness of the sandwich structure, the upper skin 130, the core structure 9 and the lower skin 140 are all positioned between the two press rolls during pressing, and after the pressing by the press rolls, the upper skin 130 and the lower skin 140 are pressed and fixed on the core structure 9. The sandwich forming roll 13 also serves to provide a traction force, which pulls the upper skin 130 and the lower skin 140 into the sandwich forming roll 13 while pressing, while the core structure 9 enters the sandwich forming roll 13 under the traction of the sandwich forming roll 13 and the transport of the core transport device 10. The core transport device 10 may be a conveyor belt or the like, preferably employing a plurality of horizontal transport shafts arranged side by side.

In order to improve the connection strength between the upper skin 130, the core structure 9 and the lower skin 140, second preheating devices 40 are arranged between the upper skin impregnation die 11 and the sandwich forming roll 13 and between the lower skin impregnation die 17 and the sandwich forming roll 13. The upper skin 130 and the lower skin 140 are preheated by the second preheating device 40 before pressing, and the preheating can be specifically carried out to 200-280 ℃ and 255 ℃ preferably, so that the resin matrixes 200 of the upper skin 130 and the lower skin 140 are softened, the flowability is enhanced, and during pressing, the resin matrixes 200 of the upper skin 130 and the lower skin 140 can be fully combined with the resin matrix 200 of the core layer structure 9, and the higher connection strength is ensured.

An upper guide roller 12 is arranged between the upper skin dipping die 11 and the interlayer forming roller 13, and a lower guide roller 16 is arranged between the lower skin dipping die 17 and the interlayer forming roller 13. The upper guide roll 12 and the lower guide roll 16 play a role of guiding so that the upper skin 130 and the lower skin 140 are in a horizontal position after coming out of the die orifice of the impregnation die, and the die orifice is prevented from scratching the upper skin 130 and the lower skin 140.

The sandwich structure is characterized by further comprising a cutting machine 15, wherein the sandwich forming roller 13, the double-steel belt press 14 and the cutting machine 15 are sequentially arranged, the cutting machine 15 is used for cutting the prepared sandwich structure into a proper length, and a conventional cutting device is adopted.

The preparation device can directly prepare the finished product of the sandwich structure by carrying out a series of treatments on the resin raw material and the fiber raw material, realizes continuous manufacture, has high manufacture efficiency, and can be used for industrial mass production.

The method for manufacturing the sandwich structure by adopting the manufacturing device of the thermoplastic composite material sandwich structure specifically comprises the following steps:

molten resin matrix, which may be polypropylene, polyethylene, nylon, polyphenylene sulfide, polyether ether ketone, etc., is introduced into the core layer impregnation die 6, the upper skin impregnation die 11, and the lower skin impregnation die 17, and is plasticized by the extruder 30 and then extruded into each impregnation die.

The core layer fiber 100, the upper skin fiber 110 and the lower skin fiber 120 are respectively pretreated by a core layer pretreatment device, an upper skin pretreatment device and a lower skin pretreatment device. The core layer fiber 100, the upper skin fiber 110 and the lower skin fiber 120 may be one or a mixture of several of carbon fiber, glass fiber, aramid fiber and basalt fiber, and the pretreatment specifically includes sequentially unreeling, pre-tightening and fiber spreading of fiber raw materials. Unreeling is carried out by a creel 1, pre-tightening is carried out by a fiber pre-tightening device 2, fiber spreading is carried out by a yarn spreading device 4, after pre-tightening, a fiber raw material is preheated to 80-300 ℃ by a first preheating device 3, and moisture and sizing agents on the surface of the fiber can be removed.

The core layer fiber 100 enters a core layer dipping die 6, the upper skin fiber 110 enters an upper skin dipping die 11, the lower skin fiber 120 enters a lower skin dipping die 17, and an upper skin 130, a plane core layer and a lower skin 140 are formed after dipping of the resin matrix. After impregnation, the upper skin 130, the planar core layer and the lower skin 140 have a thickness in the range of 0.1-2mm and a width in the range of 8-1000mm, and the size of the upper skin, the planar core layer and the lower skin can be controlled by the size of the die orifice of the impregnation die.

Go up covering 130, plane sandwich layer and covering 140 are the flat plate shape down, go up covering 130 and covering 140 need not change the shape again down, can directly get into intermediate layer forming roll 13, and the plane sandwich layer need the shaping reentrant intermediate layer forming roll 13 behind the trapezoidal waveform, the hot pressing forming roll 7 of specific utilization and the chill roll forming roll 8 are extruded the plane sandwich layer successively, trapezoidal setting tooth 20 on hot pressing forming roll 7 and the chill roll forming roll 8 mutually support, can become trapezoidal waveform with the extrusion of plane sandwich layer, obtain trapezoidal waveform's sandwich layer structure 9.

The hot-pressing temperature of the hot-pressing shaping roller 7 is 10-50 ℃ lower than the melting point of the resin matrix, so that the resin matrix 200 has higher temperature, stronger plasticity and easy deformation, the extrusion forming difficulty is reduced, the cold-pressing temperature of the cold-pressing shaping roller 8 is 50-100 ℃, and the internal stress of the core layer structure 9 is released through hot-cold twice extrusion, so that the shape is kept stable.

The sandwich layer transmission device 10 conveys the sandwich layer structure 9 to a sandwich layer forming roller 13, the upper skin 130, the sandwich layer structure 9 and the lower skin 140 are sequentially arranged from top to bottom, the sandwich layer forming roller 13 presses and fixes the upper skin 130 on the upper surface of the sandwich layer structure 9, and presses and fixes the lower skin 140 on the lower surface of the sandwich layer structure 9, so that the sandwich layer structure is obtained.

In order to improve the connection strength, before entering the interlayer forming roller 13, the upper skin 130 and the lower skin 140 are preheated to 200-280 ℃, after the temperature is increased, the resin matrix 200 is softened, the fluidity is enhanced, and during extrusion, the resin matrix 200 of the upper skin 130 and the lower skin 140 can be fully combined with the resin matrix 200 of the core layer structure 9 into a whole, so that the sufficient connection strength is ensured.

And finally, cooling and shaping the sandwich structure by using a double-steel belt press 14 to obtain the sandwich structure with a stable structure.

The invention has the following advantages:

1. the sandwich structure has larger thickness and avoids overlarge weight of the sandwich structure due to the adoption of the trapezoidal waveform sandwich layer structure 9, in addition, the sandwich layer structure 9 has good rigidity and high strength, and the upper skin 130, the sandwich layer structure 9 and the lower skin 140 are all reinforced by fibers, so that the strength is further improved, and the performances of pressure resistance, bending resistance and the like are better.

2. Anti-delamination: the upper skin 130, the lower skin 140 and the core layer structure 9 are made of the same material, and have stronger delamination resistance compared with the traditional sandwich structure composite material.

3. The product form is diversified: the reinforcement can be one or a mixture of several of carbon fiber, glass fiber, aramid fiber and basalt fiber, the resin matrix can adopt polypropylene, polyethylene, nylon, polyphenylene sulfide, polyether ether ketone and the like, and the diversification of product forms is realized; the corrugated structure of the invention can be used under different working conditions.

4. The internal stress of the core layer structure material is uniformly released under the action of a hot-cold setting roller.

5. Compared with the existing interlayer mechanism, the manufacturing difficulty is low, the manufacturing efficiency is greatly improved, and the method can be used for continuous, batch and industrial production.

Example one

The sandwich structure is prepared by taking the carbon fiber of T700-12K and polyethylene as raw materials, and the preparation process comprises the following steps:

preparation of the upper skin 130: unwinding a carbon fiber raw material; pre-tightening; preheating to 80 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 0.5mm and the width is 400mm after impregnation;

preparation of the lower skin 140: unwinding a carbon fiber raw material; pre-tightening; preheating to 80 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 0.5mm and the width is 400mm after impregnation;

preparation of the core structure 9: unwinding a carbon fiber raw material; pre-tightening; preheating to 80 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 0.5mm and the width is 400mm after impregnation; hot pressing at a temperature 10 ℃ lower than the melting point of the resin matrix, and cold press molding the core layer structure 9 at a temperature of 100 ℃;

the above processes are performed synchronously.

The upper skin 130 and the lower skin 140 are preheated to 200 ℃, and the upper skin 130, the core structure 9 and the lower skin 140 are pressed and cooled.

Example two

The sandwich structure is prepared by adopting glass fiber and polypropylene as raw materials, and the preparation process comprises the following steps:

preparation of the upper skin 130: unwinding a glass fiber raw material; pre-tightening; preheating to 150 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 1.3mm and the width is 600mm after impregnation;

preparation of the lower skin 140: unwinding a glass fiber raw material; pre-tightening; preheating to 150 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 1.3mm and the width is 600mm after impregnation;

preparation of the core structure 9: unwinding a glass fiber raw material; pre-tightening; preheating to 150 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 1.3mm and the width is 600mm after impregnation; hot pressing at a temperature 20 ℃ lower than the melting point of the resin matrix, and cold press molding the core layer structure 9 at a temperature of 80 ℃;

the above processes are performed synchronously.

The upper skin 130 and the lower skin 140 are preheated to 255 ℃, and the upper skin 130, the core structure 9 and the lower skin 140 are pressed together and cooled.

EXAMPLE III

The preparation method adopts basalt fibers and polyphenylene sulfide as raw materials to prepare the sandwich structure, and comprises the following steps:

preparation of the upper skin 130: unreeling basalt fiber raw materials; pre-tightening; preheating to 300 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 2mm and the width is 1000mm after impregnation;

preparation of the lower skin 140: unreeling basalt fiber raw materials; pre-tightening; preheating to 300 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 2mm and the width is 1000mm after impregnation;

preparation of the core structure 9: unreeling basalt fiber raw materials; pre-tightening; preheating to 300 ℃; spreading yarns; impregnating the resin matrix 200, wherein the thickness is 2mm and the width is 1000mm after impregnation; hot pressing at a temperature 50 ℃ lower than the melting point of the resin matrix, and cold press molding the core layer structure 9 at a temperature of 50 ℃;

the above processes are performed synchronously.

The upper skin 130 and the lower skin 140 are preheated to 280 ℃, and the upper skin 130, the core structure 9 and the lower skin 140 are pressed together and cooled.

The sandwich structures prepared in examples one to three were tested for strength as shown in the following table

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Thermoplastic composite sandwich structure's serialization becomes molding device which characterized in that: the device comprises an upper skin pretreatment device, a lower skin pretreatment device, a core layer pretreatment device, an upper skin dipping die (11), a lower skin dipping die (17), a core layer dipping die (6), a core layer shaping device, a core layer transmission device (10), an interlayer forming roller (13) and a double-steel belt press (14);

the sandwich layer pre-treatment device, the sandwich layer dipping die (6), the sandwich layer shaping device, the interlayer forming roller (13) and the double-steel belt press (14) are sequentially arranged, the sandwich layer shaping device comprises a set of hot-pressing shaping roller (7) and a set of cold-pressing shaping roller (8), the outer walls of the hot-pressing shaping roller (7) and the cold-pressing shaping roller (8) are both provided with uniform shaping teeth (20), the length direction of the shaping teeth (20) is the axial direction of the hot-pressing shaping roller (7) and the cold-pressing shaping roller (8), and the section of the shaping teeth (20) is trapezoidal;

the upper skin pretreatment device is connected with the upper skin dipping die (11), the lower skin pretreatment device is connected with the lower skin dipping die (17), and the upper skin dipping die (11) and the lower skin dipping die (17) are respectively positioned above and below the core layer transmission device (10).

2. A continuous forming apparatus for sandwich structures of thermoplastic composite material according to claim 1, characterized in that: the upper skin pretreatment device, the lower skin pretreatment device and the core layer pretreatment device are the same and respectively comprise a creel (1), a fiber pre-tightening device (2) and a yarn spreading device (4) which are arranged in sequence.

3. A continuous forming apparatus for sandwich structures of thermoplastic composite material according to claim 2, characterized in that: a fiber width-fixing roller (5) is arranged between the yarn spreading device (4) and the core layer dipping die (6);

a first preheating device (3) is arranged between the fiber pre-tightening device (2) and the yarn spreading device (4);

the upper skin dipping die (11), the lower skin dipping die (17) and the core layer dipping die (6) are all connected with an extruder (30);

an upper guide roller (12) is arranged between the upper skin dipping die (11) and the interlayer forming roller (13), and a lower guide roller (16) is arranged between the lower skin dipping die (17) and the interlayer forming roller (13);

and second preheating devices (40) are arranged between the upper skin dipping die (11) and the interlayer forming roller (13) and between the lower skin dipping die (17) and the interlayer forming roller (13).

4. A continuous forming apparatus for sandwich structures of thermoplastic composite material according to claim 1, characterized in that: the double-steel belt press is characterized by further comprising a cutting machine (15), wherein the interlayer forming roller (13), the double-steel belt press (14) and the cutting machine (15) are sequentially arranged.

5. A method for molding a sandwich structure using the apparatus for continuously molding a thermoplastic composite sandwich structure according to claim 1, comprising:

introducing a molten resin matrix into a core layer dipping die (6), an upper skin dipping die (11) and a lower skin dipping die (17), respectively pretreating a core layer fiber (100), an upper skin fiber (110) and a lower skin fiber (120) by a core layer pretreatment device, an upper skin pretreatment device and a lower skin pretreatment device, allowing the core layer fiber (100) to enter the core layer dipping die (6), allowing the upper skin fiber (110) to enter the upper skin dipping die (11), allowing the lower skin fiber (120) to enter the lower skin dipping die (17), forming an upper skin (130), a plane core layer and a lower skin (140) by dipping of the resin matrix, sequentially extruding the plane core layer by a hot-pressing sizing roller (7) and a cold-pressing sizing roller (8) to obtain a trapezoidal waveform core layer structure (9), and conveying the core layer structure (9) to a sandwich layer forming roller (13) by a core layer conveying device (10), and the interlayer forming roller (13) is used for pressing and fixing the upper skin (130) on the upper surface of the core layer structure (9), pressing and fixing the lower skin (140) on the lower surface of the core layer structure (9) to obtain the interlayer structure, and finally, the interlayer structure is cooled and shaped by using the double-steel belt press (14).

6. The method of forming a sandwich structure according to claim 5, wherein: the pretreatment comprises the steps of sequentially unreeling, pre-tightening and fiber unfolding the fiber raw material; after pre-tightening the fiber raw material, the fiber raw material is preheated to 80-300 ℃ by utilizing a first preheating device (3).

7. The method of forming a sandwich structure according to claim 5, wherein: after impregnation, the upper skin (130), the planar core layer and the lower skin (140) have a thickness in the range of 0.1-2mm and a width in the range of 8-1000 mm.

8. The method of forming a sandwich structure according to claim 5, wherein: the core layer fiber (100), the upper skin fiber (110) and the lower skin fiber (120) are one or a mixture of carbon fiber, glass fiber, aramid fiber and basalt fiber; the resin matrix is one of PP, PE, PA, PPS and PEEK plastics.

9. The method of forming a sandwich structure according to claim 5, wherein: the hot-pressing temperature of the hot-pressing shaping roller (7) is 10-50 ℃ lower than the melting point of the resin matrix, and the cold-pressing temperature of the cold-pressing shaping roller (8) is 50-100 ℃; the upper skin (130) and the lower skin (140) are preheated to 200-280 ℃ before entering the interlayer forming roller (13).