WO2023103110A1

WO2023103110A1 - Processing method for one-step forming of continuous fiber-reinforced composite pipe

Info

Publication number: WO2023103110A1
Application number: PCT/CN2021/141396
Authority: WO
Inventors: 黄剑; 汪鹏跃; 孙华丽; 陈卫; 丁杰; 钱杨
Original assignee: 公元股份有限公司
Priority date: 2021-12-10
Filing date: 2021-12-25
Publication date: 2023-06-15
Also published as: CN114161745A; CN114161745B

Abstract

A processing method for one-step forming of a continuous fiber-reinforced composite pipe, belonging to the technical field of composite pipe processing. The method solves the existing problem of easy detachment between multiple composite layers of a pipe. The method comprises: wrapping the circumferential surface of an outer pipe (3) in several axial fiber layers formed by continuous fibers distributed along the axial direction of the outer pipe (3), and winding a winding fiber layer wound in the circumferential direction of the outer pipe (3) outside the axial fiber layer to form a continuous fiber-reinforced layer; enabling the continuous fiber-reinforced layer to move forward along the axial direction of the outer pipe (3), and to enter and continuously pass through a mold cavity (2c) from a gap between the inner peripheral wall of an outer mold sleeve (2a) of a forming mold (2) and the outer peripheral wall of the outer pipe (3); and compounding a molten thermoplastic material melt injected into the mold cavity (2c) with the fiber-reinforced layer continuously passing through the mold cavity (2c) to form a pipe blank, and cooling the pipe blank to obtain a corresponding composite pipe. The processing can be completed in a one-step manner, and the pipe has the advantage of high shear strength.

Description

A processing method for one-step forming of continuous fiber reinforced composite pipe

technical field

The invention belongs to the technical field of composite pipe processing, and relates to a processing method for one-step forming of a continuous fiber reinforced composite pipe.

Background technique

With the continuous expansion of cities and the continuous extraction of oil and natural gas, the demand for transportation pipelines is also increasing. Traditional steel pipes have poor corrosion resistance and are not easy to handle, so they can no longer meet the current needs. At the same time, my country's main oil and natural gas are mostly distributed in deserts, swamps or mountainous areas, and the natural environment is relatively harsh. When laying steel pipelines, it is seriously affected by the natural environment, and due to ground subsidence, landslides and other reasons, the pipelines are extremely prone to damage. Phenomenon. Due to its low density, high strength, and excellent mechanical properties, such as good processing performance, good chemical resistance and heat resistance, fiber reinforced composite pipes can still be used stably for a long time in some complex environments. Therefore, it is widely used.

Existing fiber-reinforced composite pipes are mainly continuous fiber-reinforced composite pipes, and plastic pipes generally include three layers of inner layer, reinforced layer and outer layer from the inside to the outside. The pipe blank is first extruded through the extruder, and then the reinforcing layer (reinforcing fiber) is wound on the surface of the inner tube blank by a winding machine to form a corresponding reinforcing layer, and then the outer layer is compounded with a plastic layer to form a reinforcing fiber. Composite piping. Such as the Chinese patent document (publication number: CN109664479A) discloses a plastic pipe forming assembly line. The composite pipe produced by this manufacturing process needs to be wound in multiple layers to ensure that the prepared pipe reaches the required strength. However, the thickness of the continuous fiber is very large. Small, the bonding layer formed by direct winding on the surface of the inner tube is very small. At the same time, the winding of each layer of fibers in turn often results in limited or no bonding in the contact area between the fibers, resulting in poor bonding between layers. It is strong, and the delamination between the layers is obvious, resulting in insufficient shear strength between the layers, which is easy to cause damage to the pipeline during use. Another example is the continuous fiber-reinforced thermoplastic pipe and its production method disclosed in the Chinese patent document (Notice No.: CN105003753B). The inner layer is formed by wrapping a thermoplastic film or sheet evenly on a metal mandrel in a winding or longitudinal manner. Then weave or wind the fiber pre-impregnated with thermoplastic material on the inner layer or longitudinally on the surface of the inner layer, enter the mold cavity under the action of the tractor to heat, reach the predetermined temperature, melt the thermoplastic material, and use it on the side The extruder pressurizes and extrudes the supplementary material to integrate the three-layer structure into one, and forms a thermoplastic protective layer on the surface, and then sizing, cooling and shaping, cutting and other processes to obtain the final pipe, which still requires the inner layer first , The inner layer and the thermoplastic material in the mold are not formed synchronously, and there will also be problems of weak interlayer bonding and insufficient shear strength between layers.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned problems in the existing technology, and propose a processing method for one-step forming of continuous fiber-reinforced composite pipes. Interlayer adhesion and shear strength.

The object of the present invention can be achieved through the following technical solutions: a processing method for one-step molding of a continuous fiber reinforced composite pipe, characterized in that the method comprises the following steps:

A. On the peripheral surface of the outer tube of the molding device, an axial fiber layer is formed by wrapping a number of continuous fibers distributed along the axial direction of the outer tube, and a wound fiber layer wound along the circumferential direction of the outer tube is wound outside the axial fiber layer , the axial fiber layer and the winding fiber layer together form a continuous reinforcing fiber layer;

B. Under the action of traction, the continuous fiber reinforced layer moves forward along the axial direction of the outer tube, and the continuous reinforced fiber layer enters the molding from the gap between the inner peripheral wall of the outer mold sleeve of the forming mold and the outer peripheral wall of the outer tube The mold and continuously passes through the mold cavity in the forming mold;

C. The molten thermoplastic material melt injected into the mold cavity is compounded with the continuously passing continuous fiber reinforced layer to form a tube blank, and after cooling, the corresponding continuous fiber reinforced composite tube is obtained.

The present invention does not need to place the inner tube blank on the outer tube in advance, and directly distributes the continuous fiber on the circumferential surface of the outer tube by braiding, winding, etc. to form a corresponding fiber reinforcement layer. The fiber-reinforced layer can be formed by winding machines and other equipment; after the fiber-reinforced layer is directly formed on the peripheral surface of the outer tube, the fiber-reinforced layer is directly drawn into the mold cavity of the forming mold under the traction force of the tractor. Then, in the forming mold, the molten thermoplastic material injected into the mold cavity is combined with the passing fiber reinforced layer to form a pipe at one time, and when the molten thermoplastic molding material melt is injected into the cavity of the forming mold, It will also form a certain pressure, which can be well combined with the permeable reinforcing fiber layer to form a thermoplastic layer, and because it is directly compounded in one step, the thermoplastic molten material is formed simultaneously, and the compatibility between materials is very good. Good and uniform penetration, avoiding the problem of weak bonding between layers, so that the formed pipe has a high shear strength performance effect, and there is no need to pre-coat the inner tube blank on the surface of the outer tube, greatly It simplifies the operation and is more conducive to industrial production. The subsequent general cooling treatment is used to cool and shape the corresponding continuous fiber reinforced composite pipe to achieve the advantages of continuous production.

In the one-step forming method of the continuous fiber reinforced composite pipe, preferably, the continuous fiber reinforced layer in step B enters the mold cavity of the forming mold and undergoes pre-wet treatment first. Because the fiber itself has microcracks, by directly pre-wetting in the mold cavity of the forming mold, due to the certain internal pressure in the mold, the molten thermoplastic melt can be better penetrated into the internal microcracks of the fiber , to make the inside of the fiber penetrate evenly, further improve the effect of fiber reinforcement, and due to the penetration and filling of the microcracks of the fiber itself through pre-soaking, it can effectively avoid internal microcracks and voids, and can also better enhance fiber reinforcement. The compatibility between the layer and the thermoplastic material is equivalent to infiltrating the thermoplastic material in the fiber, which improves the bonding force better, and is also conducive to improving the interlayer shear strength performance of the pipeline, making the shear strength performance At the same time, because the pre-wetting is carried out directly in the mold cavity, there is no need to pre-wet the fibers, which greatly facilitates the production operation, simplifies the operation, is more conducive to one-step molding, and is conducive to the continuous production of the production line. As a further preference, the pre-soaking treatment is specifically:

The continuous fiber-reinforced layer enters the mold cavity of the forming mold and first passes through the gap between the supporting cylinder in the mold cavity and the inner peripheral wall of the outer mold sleeve of the forming mold, and the supporting cylinder is covered with thermoplastic material melt for melting The flow-through orifice through which the molten thermoplastic material melt flows pre-wets the continuous fiber-reinforced layer.

This processing method enables the support cylinder to support the passing continuous fiber reinforced layer on the one hand, so that it can move straight along the outer peripheral wall of the support cylinder and improve the forming quality of the pipeline; more importantly, the support cylinder is spread all over There is a feed hole, which can make the injected partially molten thermoplastic material flow through the feed hole, which can strengthen the fluidity and plasticizing effect of the molten thermoplastic, and can penetrate into the interior of the reinforcing fiber more effectively, and the pre-wetting is more sufficient. , to avoid the influence of the existence of microcracks inside the fiber on the strength and quality of the pipeline, and improve the overall shear strength performance.

In the above-mentioned processing method of one-step forming of continuous fiber-reinforced composite pipe, as a preference, the compounding in step C is specifically: making the molten thermoplastic material melt form corresponding thermoplastic material on the inner and outer surfaces of the continuous fiber-reinforced layer layer. After the continuous fiber reinforced layer is pre-soaked, it is then molded in the molding cavity, so that the molten thermoplastic material melt can penetrate the continuous fiber reinforced layer, and the inner and outer surfaces of the molten thermoplastic material can be coated. body, so that the formed pipe can be formed at one time, avoiding the existing step-by-step processing, especially the defect of poor interlayer bonding force in the pre-forming of the inner pipe blank, and realizing that the formed pipe has better shear strength performance .

In the one-step forming process of the continuous fiber-reinforced composite pipe, it is preferable to make the pressure in the cavity of the forming mold ≥ 2.0 MPa, so that there is a certain internal pressure, which is more conducive to infiltration forming. As a preference, the pressure in the mold cavity of the forming mold is controlled at 2.0MPa-5.0MPa. The pressure control can better ensure that the molten thermoplastic material in the mold cavity penetrates into the continuous fiber reinforcement layer. On the one hand, it can more effectively achieve sufficient infiltration during pre-wetting and improve the strength performance; on the other hand, it can also It can more effectively form a thermoplastic material layer of corresponding thickness on both the inner and outer sides of the fiber reinforced layer; at the same time, it can also more effectively ensure the advantages of preventing the overflow of molten material caused by excessive pressure in the mold cavity during processing . As a further preference, it is best to control the pressure in the mold cavity of the forming mold at 2.5MPa-4.0MPa.

In the above-mentioned processing method of one-step forming of continuous fiber-reinforced composite pipe, as a preference, under the action of traction described in step B, specifically:

First, the axial fiber layer is pulled by the tractor in the traction process to drive the entire continuous fiber reinforced layer to move forward. After the composite pipe is formed, it enters the traction process, and then the composite pipe is moved forward by the tractor in the traction process to drive the continuous fiber. Enhancement layers are moved forward. Since the axial fiber layer is first pulled to move, it means that the direction of the traction force is consistent with the direction of the axial fiber, that is, both are along the axial direction of the outer tube, which can drive the entire continuous fiber reinforced layer to move forward at the same time , it is more effective to ensure that it will not loosen, and it is more conducive to maintaining its strength performance; and the subsequent direct traction and compounding will drive the continuous fiber reinforced layer to move forward continuously, which is also to better achieve uniform traction and stability. better.

In the above-mentioned one-step forming processing method of the continuous fiber reinforced composite pipe, preferably, the temperature in the forming mold is controlled at 180°C to 200°C. It can better maintain the fluidity of the injected thermoplastic material and make it into a fluid state, which can better improve its penetration ability on the fiber material, and is also more conducive to improving the overall shear strength performance.

In the above-mentioned one-step forming processing method of the continuous fiber-reinforced composite pipe, preferably, the thermoplastic material is PVC material, PP material or PE material.

Compared with the prior art, the present invention has the following advantages:

1. By directly coating the continuous fiber-reinforced layer on the outer tube surface of the molding equipment, and then continuously passing it through the mold cavity, the injected melt and the fiber-reinforced layer are composited and synchronously formed at one time to obtain the corresponding pipe. The compatibility between them is good and the penetration uniformity is good, which effectively avoids the problem of weak bonding between layers. The formed pipe has high shear strength performance, and there is no need to pre-process the inner pipe blank, which simplifies the operation.

2. Through the pre-wet treatment in the mold cavity, and under the support of the support cylinder and the existence of the feed hole, the pre-wet process can be more fully penetrated into the interior of the fiber, and the internal micro-cracks can be fully filled. It also ensures the uniformity and compatibility of penetration, improves the overall shear strength performance, and makes the shear strength performance reach more than 10MPa.

Description of drawings

Fig. 1 is the whole flow structure schematic diagram of the forming equipment of the production line in the method of the present invention.

Fig. 2 is a schematic perspective view of the part of the molding equipment before the vacuum setting process in the method of the present invention.

Fig. 3 is a schematic cross-sectional structural view of the part of the forming equipment before the vacuum setting process in the method of the present invention.

FIG. 4 is a schematic diagram of a partially enlarged structure in FIG. 3 .

Fig. 5 is a schematic perspective view of the three-dimensional structure of the support cylinder in the mold cavity of the forming mold.

In the figure, 1, extruder; 11, discharge pipe; 2, forming mold; 2a, outer mold sleeve; 2b, mandrel; 2b1, splitter; 2c, mold cavity; 2d, annular cavity; 2e, support barrel; 2e1, feed hole; 3, outer tube; 4, core tube; 41, connecting sleeve; 5, winding machine; 6, vacuum calibrating box;

Detailed ways

The following is a specific embodiment of the present invention and in conjunction with the accompanying drawings, further describes the technical solution of the present invention, but the present invention is not limited to this embodiment.

Embodiment one

As shown in Figure 1-2, the production line of the continuous fiber reinforced composite pipe one-step forming method may include an extruder 1, a forming die 2, a winding machine 5, a vacuum calibrating box 6, a tractor 7 and a pipe cutting machine 8, etc. The formed continuous processing composite pipe production line. More specifically, referring to Fig. 3 and Fig. 4, a mold cavity 2c is formed between the outer mold casing 2a and the core mold 2b of the above-mentioned forming mold 2, and the molding equipment also includes an outer tube 3 and a core tube 4, the outer tube 3 One end of the outer mold casing 2a extends into the outer mold casing 2a from the front port 2a1, and an annular cavity 2d for reinforcing fibers to pass is formed between the outer peripheral wall of the outer tube 3 and the inner peripheral wall of the outer mold casing 2a, and the mold cavity 2c There is a cylindrical support tube 2e set on the outside of the mandrel 2b. Referring to Figures 3-5, the support tube 2e is provided with feeding holes 2e1 all over, and the outer peripheral wall of the support tube 2e and the outer mold casing 2a There is a gap between the inner peripheral walls, and there is a gap between the outer peripheral wall of the mandrel 2b and the inner peripheral wall of the support tube 2e. Here, it is better to make the support tube 2e and the outer mold cover 2a concentrically arranged, and the outer peripheral wall of the support tube 2e and the The outer peripheral wall of the outer tube 3 is flush. There is a gap between the outer peripheral wall of the mandrel 2b and the inner peripheral wall of the support cylinder 2e, so that the molten material can flow through the gap smoothly, reach the rear end of the support cylinder 2e and meet and recombine with the reinforcing fibers, and part of the molten material can pass through the support cylinder The feeding hole 1e1 on 2e, the most important purpose of this process is to better pre-wet the reinforcing fibers, so that the molten thermoplastic can better penetrate into the interior of the fibers and fill them well Microcracks improve the sufficiency of penetration and avoid the influence of microcracks inside the fiber on the strength of the pipeline. A splitter 2b1 is connected to the front end of the mandrel 2b, and the support cylinder 2e is fixedly connected to the splitter. The structure of the front splitter 2b1 of the mandrel 2b can be conventional technology, that is, the splitter 2b1 is located on the side close to the core tube 4 .

As shown in FIG. 3 and FIG. 4 , the outer tube 3 is also provided with a feeding channel for injecting molten thermoplastic melt into the mold cavity 2c. Specifically, the outer tube 3 is pierced with a core tube 4 communicating with the discharge pipe 11 of the extruder 1, the core tube 4 penetrates from the other end of the outer tube (the end away from the molding die 2), and the core tube The inner hole of 4 is the above-mentioned feed channel, the outlet of the core pipe 3 is directly opposite to the flow divider 2b1, and the molten thermoplastic melt extruded by the extruder 1 is transported through the core pipe 4 and enters the mold cavity through the flow divider 2b1 . Such a delivery method will not affect the direct winding of the reinforcing fibers on the outer peripheral wall of the outer tube 3 , and is conducive to realizing the advantage of directly winding the fibers on the surface of the outer tube 3 . The outlet of the core tube 4 is directly opposite to the flow divider 2b1, so that the flow divider can spread the molten thermoplastic melt flowing out of the core tube 4 radially to the surroundings, which is convenient for heating and plasticizing the molten material, and can better ensure the melting Compounding of thermoplastic melts and fibers. A connecting sleeve 41 can also be fixed at the outlet end of the core tube 4, the outer peripheral wall of the connecting sleeve 41 is against the inner peripheral wall of the outer tube 3, the flow divider 2b1 is fixedly connected to the connecting sleeve 41 by a fastener, and the supporting tube 2e can be fixedly connected to the shunt 2b1. For example, it is best to have eight bolt through holes along its circumference on the connecting sleeve 41, and eight bolt holes corresponding to the bolt through holes are provided on the shunt, and each bolt through hole is pierced There are bolts, and the bolts pass through the bolt through holes and are screwed to the corresponding bolt holes for fixed connection.

In the process of producing the composite pipe, the composite pipe manufactured is pulled forward by the traction force of the tractor 7, so that the pipe continuously moves forward from the die of the forming die 2, and the After the mouth die comes out, it plays a sizing effect, and then enters the vacuum calibrating box 6 for cooling. The vacuum calibrating box 6 here is an existing equipment, and the cooling specific treatment in the vacuum calibrating box 6 also adopts the prior art. Further here The cooling treatment is specifically to cool the tube blank through the cooling water in the vacuum calibrating box 6 to achieve the effect of cooling and solidification, and then enter the subsequent cutting process for cutting to realize the continuous production of composite tubes. Equipment such as above-mentioned pulling machine 7, winding machine 5, pipe cutting machine 8 are prior art.

The processing method specific to the one-step forming of the continuous fiber reinforced composite pipe of the present invention can be realized by the following methods:

On the pipe processing production line, the peripheral surface of the outer tube 3 of the molding equipment is wrapped with an axial fiber layer formed by a number of continuous fibers distributed along the axial direction of the outer tube 3. Here, the fibers on the fiber unwinding device can be continuous. Pulling a number of continuous fibers distributed axially along the outer tube 3, so that the formed axial fiber lines are directly wrapped around the outer tube 3 to form an axial fiber layer, and or synchronously wound outside the axial fiber layer along the outer tube for 3 weeks The fiber wires wound in the direction are formed on the outer surface of the axial fiber layer to form a wound fiber layer, and the above-mentioned axial fiber layer and the wound fiber layer together form a continuous fiber reinforcement layer; the above-mentioned wound fiber layer can be processed according to the winding Different winding methods can be used, for example, it can be formed by weaving, or it can be wound continuously in the circumferential direction. The winding machine 5 in the prior art can be used to process the continuous fiber reinforced layer. After the corresponding continuous fiber reinforced layer is processed directly outside the outer tube 3, the next process is continuously entered;

Specifically, under the traction force of the tractor 7, the above-mentioned continuous fiber-reinforced layer is pulled to move forward along the circumferential surface of the outer tube 3, and the continuous fiber-reinforced layer is drawn from the inner peripheral wall of the outer mold casing 2a of the forming mold 2 and the annular cavity between the outer peripheral wall of the outer tube 3 enters the molding die 2 and passes through the mold cavity 2c in the molding mold 2 continuously; the melted thermoplastic material melt injected into the mold cavity 2c is reinforced with the continuous passing fiber Layers are composited to form a tube blank, and the tube blank coming out of the die of the forming mold 2 moves forward into the vacuum calibrating box 6 for cooling to obtain a corresponding continuous fiber-reinforced composite tube. Here, the amount of fiber winding and the control of the fiber amount of the axial fiber layer can be adjusted according to requirements, such as adjustments can be made according to different requirements for ring stiffness.

Further speaking, the thermoplastic material can be extruded through the core tube 4 through the existing extruder 1, so that the thermoplastic material enters the heated molten state in the core tube 4 and injects it into the mold cavity 2c of the molding die; the above The continuous fiber reinforced layer enters the mold cavity 2c of the forming mold 2 and undergoes pre-wet treatment first. The pre-soaking treatment here is specifically:

After the continuous fiber reinforced layer enters the mold cavity 2c of the molding die 2, it first passes through the gap between the support cylinder 2e in the mold cavity 2c and the inner peripheral wall of the outer mold sleeve 2a of the molding die 2, and injects molten thermoplastic through the core tube 4. The plastic material melt enters the mold cavity 2c through the flow divider, and a part of the melted thermoplastic material melt can flow through the feed hole 2e1, and the molten thermoplastic material melt flowing through the feed hole 2e1 is opposite to the passing continuous fiber The reinforcing layer is pre-wetted, and after pre-wetting, it enters the rear end of the mold cavity 2c and enters the final molding to obtain the composite tube blank. After the tube blank comes out of the die of the forming mold 2, it moves forward and enters the vacuum calibrating box 6 for final molding. After cooling and other processes, the cooling water (cooling liquid) in the vacuum calibrating box 6 is used to cool the tube blank to cool and solidify to achieve a certain shaping effect, and then it is pulled by the tractor 7 to move forward and enter the cutting process through the tube cutting machine. 8. Cut according to the actual length to obtain the finished composite pipe.

In a more preferred solution, the above-mentioned production and processing should preferably control the injection pressure above 2.0MPa, which is equivalent to controlling the pressure in the mold cavity 2c of the forming mold 2 to be greater than or equal to 2.0MPa. More preferably, the pressure in the mold cavity 2c of the forming mold 2 is controlled at 2.0MPa～5.0MPa, which can be controlled by regulating the pressure of the molten thermoplastic material melt injected from the core tube 4, so that the pressure in the mold cavity 2c With a certain pressure, it is more conducive to penetrate into the interior of the fiber and overcome the effect of internal microcracks, and keeping it under the above pressure can better make the formed pipeline one-step method directly form the corresponding thermoplastic on the inner and outer surfaces of the fiber reinforced layer. material layer. The overall consistency is good, which is more conducive to improving the shear strength performance of the pipeline, and can also well prevent the material in the mold cavity 2c from overflowing. As a better preference, it is best to control the pressure at 2.5MPa-4.0MPa, more preferably at 3.5MPa. It is also possible to make the continuous fiber reinforced layer move forward at a speed of 0.25m/min to 1.0m/min. Or preferably, the ratio of the pressure value to the speed value can be 5-10.

When the composite pipe is processed above, at the beginning, the axial fiber layer is pulled by the tractor 7 in the traction process to drive the entire continuous fiber reinforced layer to move forward. After the composite pipe is formed, the tractor 7 in the traction process moves forward. The traction composite pipe moves forward to drive the continuous fiber reinforced layer to move forward, which can more effectively maintain the traction force, and at the same time ensure the integrity of the continuous fiber reinforced layer during the early traction, avoid loosening and reduce material waste. That is to say, it is understood that at the beginning of processing and production, the axial fiber layer is pulled by the tractor 7 in the early stage to make the whole move forward, and after the pipe is formed, the composite pipe is pulled forward to move. It is equivalent to moving the traction forward through continuous traction of the composite pipe during the continuous production and processing of the production line.

The temperature inside the forming mold 2 is controlled at 180° C. to 200° C. to maintain the fluidity of the material, so that it can be better combined with the continuous fiber reinforced layer, and can better ensure sufficient penetration inside the fiber. Here, it is preferable to control the temperature of the forming mold 2 in three stages, so as to have better heat preservation ability, better fluidity of the material in the mold cavity 2c, and improve its penetration ability to fibers. Furthermore, there may be several sections of heating regions on the outer circumferential division of the core tube 4 located in the outer tube 3 . It is beneficial to ensure that the plastic melt can better handle the molten state.

The above-mentioned thermoplastic material can be PVC material, PP material or PE material, preferably PE material is used for processing. The above-mentioned continuous fibers are preferably made of glass fiber material as the fiber material of the axial fibers and the winding fibers.

The following specifically adopt PE material as thermoplastic material to process pipes, and use glass fibers as fiber materials to process corresponding composite pipes, and the obtained pipes are put into performance tests, and the results show that the above-mentioned continuous fiber reinforced composite pipes obtained by the method of the present invention are The shear strength between layers is ≥10MPa. It shows that the obtained composite pipe has good interlayer composite compatibility and good bonding force.

Embodiment two

The production line mentioned in Embodiment 1 can be used to enter the pipeline production. Under the traction force of the tractor 7, the continuous glass fiber on one of the winding machines 5 is drawn to the outer peripheral surface of the outer pipe 3, and the winding is carried out by pulling A number of continuous fibers distributed along the axial direction of the outer tube 3 on the machine 5, so that the formed axial fiber lines are directly wrapped on the circumferential surface of the outer tube 3 to form an axial fiber layer into a tubular shape, and then pulled by another winding machine 5. The upper fibers are synchronously formed on the outer surface of the axial fiber layer along the fiber lines wound in the circumferential direction of the outer tube 3 outside the axial fiber layer to form a wound fiber layer, which may be a wound fiber layer formed in a 45° cross weaving manner, The above-mentioned axial fiber layer and winding fiber layer together form a continuous fiber reinforced layer, which continuously enters the next process under the action of traction;

After entering the next process, under the traction force of the traction machine 7 in the above-mentioned traction process, the above-mentioned continuous fiber reinforced layer is pulled to move forward along the circumferential surface of the outer tube 3, and the continuous fiber reinforced layer is drawn from the mold 2 The annular cavity between the inner peripheral wall of the outer mold casing 2a and the outer peripheral wall of the outer tube 3 enters the forming mold 2 and passes continuously through the cavity 2c in the forming mold 2, where the ring-forming cavity allows the continuous fiber reinforced layer to enter At the same time, it can avoid the melt overflow in the mold cavity; extrude the PE thermoplastic material through the extruder 1 and inject the melted thermoplastic material melt into the mold cavity 2c through the core tube 4 to compound with the continuously passing continuous fiber reinforced layer To form a tube blank, the above-mentioned continuous fiber reinforced layer enters the mold cavity 2c of the forming mold 2 and undergoes pre-wet treatment first. The pre-soaking treatment here is specifically:

After the continuous fiber reinforced layer enters the mold cavity 2c of the molding die 2, it first passes through the gap between the support cylinder 2e in the mold cavity 2c and the inner peripheral wall of the outer mold sleeve 2a of the molding die 2, and injects molten thermoplastic through the core tube 4. The plastic material melt enters the mold cavity 2c through the flow divider, and a part of the molten thermoplastic material melt can flow through the feed hole 2e1 of the support cylinder 2e, and the molten thermoplastic material melt that flows through the feed hole 2e1 passes through The continuous fiber-reinforced layer is pre-soaked, and after pre-wet, it enters the rear end of the cavity 2c for final molding, so that the molten thermoplastic material melt and the continuous fiber-reinforced layer are completely compounded to obtain a composite tube blank. After coming out of the die of the forming mold 2, move forward and enter the vacuum calibrating box 6 for cooling. Specifically, the composite pipe can be cooled and solidified by the cooling water (cooling liquid) in the vacuum calibrating box 6 to achieve a certain shape. As a result, the traction of the tractor 7 in the traction process moves forward and enters the cutting process and cuts according to the actual length by the pipe cutter 8 to obtain a finished composite pipe. The inner and outer surfaces of the composite pipe are compounded with the above-mentioned PE thermoplastic material layer.

During the above-mentioned continuous production and processing process, the pressure in the mold cavity 2c of the forming mold 2 is controlled at 3.5MPa, which is equivalent to controlling the injection pressure at 3.5MPa. By regulating the pressure of the molten thermoplastic material melt injected from the core tube 4 Control so that there is a certain pressure in the mold cavity 2c, which is more conducive to penetrating into the interior of the fiber and overcoming the effect of internal microcracks, and keeping the above pressure can better make the formed pipeline one-step method directly in the fiber reinforced layer. Corresponding layers of thermoplastic material are formed on both the inner and outer surfaces. It is more conducive to improving the shear strength performance of the pipeline, and can also well prevent the material in the mold cavity 2c from overflowing. It is also preferable to simultaneously make the continuous fiber reinforced layer move forward at a speed of 0.5 m/min.

The obtained pipe was put into a performance test, and the result showed that the interlayer shear strength of the continuous fiber-reinforced composite pipe obtained by the method of the present invention was 15 MPa. It shows that the obtained composite pipe has good interlayer composite compatibility and good bonding force.

The specific embodiments described in the present invention are only to illustrate the spirit of the present invention. Those skilled in the art to which the present invention belongs can make various modifications or supplements to the described specific embodiments or adopt similar methods to replace them, but they will not deviate from the spirit of the present invention or go beyond the definition of the appended claims range.

Although this paper uses more extruder 1; discharge pipe 11; forming mold 2; outer mold sleeve 2a; core mold 2b; mold cavity 2c; ; Connecting sleeve 41; Winding machine 5; Vacuum calibrating box 6; Traction machine 7; These terms are used only for the purpose of describing and explaining the essence of the present invention more conveniently; interpreting them as any kind of additional limitation is against the spirit of the present invention.

Claims

A processing method for one-step forming of a continuous fiber reinforced composite pipe, characterized in that the method comprises the following steps:

A. On the peripheral surface of the outer tube (3) of the molding device, wrap a number of axial fiber layers formed by continuous fibers distributed axially along the outer tube (3), and wrap the outer tube (3) outside the axial fiber layer A wound fiber layer wound in a circumferential direction, the axial fiber layer and the wound fiber layer together form a continuous fiber reinforcement layer;

B. Under the action of traction force, the continuous fiber reinforced layer moves forward along the axial direction of the outer tube (3), and the continuous fiber reinforced layer moves from the inner peripheral wall of the outer mold sleeve (2a) of the forming mold (2) to the outer tube The annular cavity between the outer peripheral walls of (3) enters the molding die (2) and passes through the mold cavity (2c) in the molding die (2) continuously;

C. The molten thermoplastic material melt injected into the mold cavity (2c) is compounded with the continuous fiber-reinforced layer to form a tube blank, and after cooling, a corresponding continuous fiber-reinforced composite tube is obtained.
The processing method for one-step forming of continuous fiber reinforced composite pipe according to claim 1, characterized in that in step B, the continuous fiber reinforced layer enters the cavity (2c) of the forming mold (2) and undergoes pre-wet treatment first.
According to the processing method of one-step forming of continuous fiber reinforced composite pipe according to claim 2, it is characterized in that the pre-soaking treatment is specifically:

The continuous fiber reinforced layer enters the mold cavity (2c) of the molding mold (2) and first passes between the support cylinder (2e) in the mold cavity (2c) and the inner peripheral wall of the outer mold sleeve (2a) of the molding mold (2). gap, the support cylinder (2e) is provided with feed holes (2e1) for the melted thermoplastic material melt to flow through the support cylinder (2e), and the melted thermoplastic material melt that flows through the feed hole (2e1) is continuous The fiber reinforced layer is pre-soaked.
According to the processing method of one-step forming of continuous fiber reinforced composite pipe according to claim 1, it is characterized in that the compounding in step C is specifically: making the melted thermoplastic material melt form corresponding pipes on the inner and outer surfaces of the continuous fiber reinforced layer. layer of thermoplastic material.
According to any one of claims 1-4, the processing method of one-step forming of continuous fiber reinforced composite pipe is characterized in that the pressure in the cavity (2c) of the forming mold (2) is controlled at 2.0MPa～5.0MPa .
According to the processing method of one-step forming of continuous fiber reinforced composite pipe according to any one of claims 1-4, it is characterized in that, under the action of traction force described in step B, it is specifically: first pass through the tractor (7) in the traction process ) pulls the axial fiber layer to drive the entire continuous fiber reinforced layer to move forward. After the composite pipe is formed, it enters the traction process, and then the tractor (7) in the traction process draws the composite pipe to move forward and drives the continuous fiber reinforced layer to move forward. move.
The processing method for one-step forming of continuous fiber reinforced composite pipe according to any one of claims 1-4, characterized in that the temperature in the forming mold (2) is controlled at 180°C to 200°C.
According to any one of claims 1-4, the processing method of one-step forming of continuous fiber reinforced composite pipe is characterized in that the thermoplastic material is PVC material, PP material or PE material.