WO2018124908A1

WO2018124908A1 - Method of producing a multi-layered reinforced polymer pipe

Info

Publication number: WO2018124908A1
Application number: PCT/RU2016/000927
Authority: WO
Inventors: Юрий Максимович ПЕТРОВ
Original assignee: Юрий Максимович ПЕТРОВ
Priority date: 2016-12-26
Filing date: 2016-12-26
Publication date: 2018-07-05

Abstract

The invention relates to techniques for manufacturing multi-layered reinforced seamless articles with a polymer matrix, by continuously producing composite polymer pipes by extrusion. According to the present method, circumferential reinforcing elements are wound helically onto a shell and a polymer matrix is then applied thereto by extrusion, followed by cooling and cutting of the pipe. The invention makes it possible to increase process productivity when manufacturing a multi-layered reinforced polymer pipe, and to reduce the energy consumed in production.

Description

METHOD FOR PRODUCING MULTILAYER POLYMERIC REINFORCED

PIPES

The invention relates to the manufacturing technology of multilayer reinforced seamless products with a polymer matrix. The specified technology includes the continuous production of composite polymer pipes by extrusion.

Various methods are known from the prior art for the production of a composite reinforced polymer pipe, according to which, in the first stage, threads or ribbons of high modulus fibers or metal wire are wound onto a mandrel in the form of a polymer billet pipe, and in the second stage, the resulting semi-finished product is coated with an outer polymer layer.

From the RF patent for invention RU 2206017, MP: F16L9 / 12, published on 10.06.2003, a method for manufacturing a multilayer reinforced polymer pipe is known, which consists in forming a polymer pipe shell from a predetermined polymer material in the first extruder. In the second stage, the outer surface of this pipe is activated, for example, by machining and / or heat treatment by heating or by applying a heat-treated polymer layer to it, for example, by winding a polymer film onto a hot polymer pipe, or by spraying molten polymer onto this pipe, as a result what is the second activated layer of the outer surface of the polymer pipe shell. At the third stage, a spiral layer of reinforcing elements made of wire, tape or cord with a given step and the direction of winding is installed on the activated layer of the shell pipe and fixed.

At the fourth stage, longitudinal reinforcement elements uniformly spaced around the circumference are fed to said spiral layer of reinforcing elements and form a longitudinal reinforcement layer onto which the outer spiral layer of wire reinforcement is wound. As winding, the outer spiral layer is welded to successively intersected elements of the longitudinal layer by the electrocontact method and a rigid frame is placed on the first elastic spiral layer. A rigid frame with an elastic layer together make up a strength amplifier mounted on a polymer pipe shell. At the fifth stage, the strength amplifier is introduced together with the shell pipe into the thermostat. In the thermostat, the strength amplifier is heated to a temperature close to the temperature of the polymer melt, but not allowing deformation of the inner polymer shell pipe. Then, at the sixth stage, the heated strength amplifier, together with the shell pipe, is fed into the molding cavity of the second extruder, into which the molten extrudable polymer is also sent. In this case, the role of the internal forming cavity is played by the polymer pipe shell itself, along the activated surface of which the matrix monolith is formed from the polymer of the inner pipe and the melt of the extruded polymer. The outer forming surface of the forming cavity is the sleeve of the extruder. Thus, in six consecutive technological steps, a multilayer reinforced pipe with a polymer matrix is obtained.

The mentioned method is very laborious, it is carried out in the form of an intermittent multi-stage process, which increases the cost of pipes and reduces the productivity of the manufacturing process. In addition, for pipes obtained by the method described above, indicators of long-term strength during operation are not guaranteed, since the means of fixing the first reinforcement layer at the ends of the pipe are not disclosed.

From the description of US patent j4s4394338, IPC: B29C47 / 02; B32B17 / 06, published July 19, 1983, a method and apparatus for manufacturing elongated products reinforced with fibers are known. The patent specification describes, by way of example, the preparation of a laminated reinforced pipe using a device comprising two extruders. Using the first extruder, a polypropylene tube is obtained, then it is cooled and subsequently used as a mandrel (shell) with an outer diameter of 34 mm and a wall thickness of 2 mm. On the outer surface of this mandrel, a fiberglass roving, previously impregnated with an unsaturated polyester binder, is longitudinally placed. The resulting assembly of materials is passed through a squeeze die, and then it is introduced into the second extruder to form the outer layer of the matrix. In the second extruder, the resulting assembly is coated with low density polyethylene. As a result, a laminated composite tube with a smooth outer surface with an internal diameter of approximately 30 mm and an external diameter of 40 mm at a production speed of 10 m / min.

The disadvantage of this method is the low resistance of the obtained pipe in relation to radial loads, since the pipe reinforcement has only a longitudinal direction. The application of the circumferential reinforcing carcass in this method is not provided.

The formation of the circumferential reinforcement with respect to the continuous manufacturing method for composite fiberglass pipes is described in US Pat. No. 4,515,737, IPC: B29C47 / 02, published on 05/07/1985. As indicated in the description of the patent, the manufacture of composite fiberglass pipes is as follows. Using the first extruder, the mandrel tube is continuously extruded from a thermoplastic resin. The resulting mandrel tube is cooled with water. After curing the extruded mandrel pipe, its surface is treated with a blower to remove moisture. At the same time, glass fibers intended for longitudinal reinforcement are fed from crests located on the sides of the processing line, which are passed through a forming device to form the roving, and then sent to the impregnation bath to impregnate the roving with a thermosetting resin. The thermosetting resin is pre-mixed with a photopolymerization initiator, a catalyst and a polymerization accelerator and continuously introduced into the impregnation bath through a pump. To control the amount of resin in the impregnated roving use pinch rollers installed in the impregnation bath. Then, the roving is aligned axially along the surface of the mandrel tube and a roving with a binder is applied to the mandrel using a die. In order to increase the strength characteristics of the finished fiberglass pipe in the circumferential direction, the glass fibers are spirally wound around the surface of the axially reinforced mandrel pipe using a winding unit. The winding unit contains a faceplate on which spools with a supply of fiberglass for winding the circumferential reinforcement are installed around the circumference. The faceplate is mounted to rotate around the longitudinal axis of the manufactured composite pipe. The winding angle can vary from 30 to 90 degrees by changing the feed rate of the extruded mandrel pipe and the rotation speed faceplates of the winding unit. After spiral winding of glass fibers of circumferential reinforcement, the assembly is subjected to compression impregnation. As a result of the crimping, the resin will start to flow out of the glass roving of the longitudinal reinforcement and impregnates the glass fibers of the circular reinforcement laid in a spiral. Then carry out the processing of the assembly by ultraviolet radiation. After that, the assembly is sent to successively installed infrared radiation furnaces to cure the thermosetting resin of the binder at a temperature in the range from 80 to 120 ° C to activate the effect of the accelerator and catalyst on the binder polymerization process. Then, using a second extruder, a thermoplastic resin coating is applied to the assembly surface, the cooling process is carried out to obtain a finished three-layer composite pipe. The finished composite pipe is continuously pulled by a pulling device and automatically cut to a predetermined length. The composite pipes of this invention have high strength, chemical resistance and abrasion resistance.

The disadvantage of the described method is the complex and energy-intensive design of equipment for winding elements of circumferential reinforcement. The specified equipment should ensure the circulation around the longitudinal axis of the formed product of the entire stock of fiberglass material, taking into account the impregnation material, intended for the formation of a circular frame with the expectation of at least one day of continuous operation. If you reduce the supply of material on the spools of the faceplate, then the number of stops of the processing line will increase significantly due to the rapid exhaustion of consumables for the transverse reinforcement of composite pipes. This circumstance reduces the indices of continuity of the manufacturing process and increases the amount of finished product waste arising from equipment shutdowns.

The claimed invention is aimed at solving the problem of increasing the productivity of the manufacturing process of a multilayer polymer reinforced pipe and reducing the cost of the resulting product while reducing the energy intensity of production, as well as simplifying equipment.

In the implementation of the claimed invention, the problem is solved by eliminating the need to create sophisticated equipment for circulating the stock of material of reinforcing elements around the longitudinal axis of the product when manufacturing of district reinforcement; reduction in the number of stops of the processing line due to the exhaustion of supplies of supplies for the district reinforcement, which increases the continuity of the manufacturing process and reduces the amount of waste products from stopping the equipment.

The technical result is to improve the quality of finished products and expand their range.

Improving the quality of finished products is achieved by reducing structural defects in a multilayer polymer reinforced pipe.

The claimed method further improves the conditions for the use of tape materials as the material of the circumferential reinforcement of composite pipes, since the kinematics of supplying consumables for the circumferential reinforcement involves the use of only transverse bending without longitudinal bending of the circular reinforcing elements.

The problem is solved as follows.

The claimed method of producing a multilayer polymer reinforced pipe, which is continuous and is implemented during a single technological stage. The method includes spiral winding of circumferential reinforcing elements onto a tubular-shaped shell and subsequent extrusion deposition on the surface of the circumferential reinforcing elements of a polymer matrix to form the outer layer of the pipe body, cooling and cutting the pipe into segments of a given length.

Moreover, before the operation of spiral winding, the peripheral reinforcing elements are fed to the bypass roller, configured to make the circumferential reinforcing elements at least one turn along the surface of the specified roller coaxially with the spiral windings, and after the bypass roller, the circumferential reinforcing elements are fed first to the guide roller, then on the pressure roller of the stacker.

The circumferential reinforcing elements are mainly based on non-metallic materials, which are preliminarily impregnated with a liquid polymer binder before winding, and after impregnation they are passed through a forming hot die and through a heating zone for preliminary incomplete polymerization of the surface layer of the binder. The shell in the formation zone of the frame is directed through the hole in the bearing support of the bypass roller, while the shell and the surrounding reinforcing elements are connected to each other under the action of the pressure roller by squeezing the liquid binder from the reinforcing elements and wetting the joint; after which the shell with the wound circumferential reinforcing element is fed into the heating zone, where the frame is glued by final polymerization of the binder; then the casing with the wound circumferential reinforcing elements is directed into the molding cavity of the extruder formed by the specified casing and the outer forming sleeve, while the polymer is injected through the offset head mounted above the casing with the wound circumferential reinforcing elements.

In the inventive method, the tubular shell is continuously formed from polymeric materials on the first extruder located in front of the bypass roller and mounted coaxially with it, or a preformed polymer tube is used as the shell.

If it is necessary to increase the diameter of the molded multilayer polymer reinforced pipe, the casing is pressed into rollers before entering the inner hole of the bypass roller with a decrease in the outer diameter, and after exiting the bypass roller, it is heated to restore the outer diameter of the casing, then the circumferential reinforcing elements are wound onto it.

To increase the longitudinal strength and rigidity of the multilayer polymer reinforced pipe before the spiral winding operation, longitudinal reinforcing elements based on non-metallic fibers impregnated with a liquid polymer binder are fed to the shell, and after impregnation, the longitudinal reinforcing elements are passed through a forming hot die and through a heating zone for preliminary incomplete polymerization of the surface layer of the binder; while the longitudinal reinforcing is directed to the shell through the holes in the bearing support of the bypass roller, and the connection between the longitudinal reinforcing elements and the circumferential reinforcing elements at the points of mutual intersection is carried out under the action of the pressure roller on the spiral winding operation. As the circumferential reinforcing elements in the claimed method, fiberglass in the form of rovings formed into bundles is preferably used.

As circumferential reinforcing elements in the claimed method, it is possible to use bundles formed from carbon fiber, from basalt fiber, from high-strength textile polyester or polyamide fiber, etc.

As circumferential reinforcing elements in the claimed method, it is possible to use a tape of any kind of non-metallic fibers, for example, fiberglass, carbon fiber, basalt fiber, high-strength textile polyester or polyamide fiber.

As longitudinal reinforcing elements in the inventive method, it is possible to use bundles or tape of non-metallic fibers, as well as a metal tape or wire.

As a result of the implementation of the claimed method, as a multilayer reinforced pipe, it is preferable to obtain a multilayer fiberglass pipe, and after cooling and cutting the manufactured pipe into segments of a given length at the ends of each pipe segment, ends made of a polymer material in the form of a sleeve with a protrusion on the end on the inner the surface of the cavity of the sleeve. In this case, the inner diameter of the tip corresponds to the outer diameter of the manufactured pipe, and the protrusion closes the reinforcing elements at the end of the pipe and allows heat sealing of the pipes in the manufacture of the pipeline.

A multilayer polymer reinforced pipe in accordance with the claimed method is made, as shown below on the example of manufacturing a multilayer fiberglass pipe.

Moreover, a device for producing a multilayer polymer reinforced pipe includes a production line consisting of sequentially installed devices interconnected along the longitudinal axis of the resulting product. The first is an extruder that continuously forms a tubular shell of polymer materials, then a bypass roller is installed, followed by a stacker of circumferential reinforcing elements containing a guide roller and a pressure roller a roller mounted on the faceplate with the possibility of rotation around the longitudinal axis of the processing line. Next, a second extruder, a cooling system, as well as a pulling mechanism and a cutting mechanism are installed. Moreover, the coil with the material of the circumferential reinforcement is located on the side of the longitudinal axis of the production line in front of the bypass roller. Auxiliary elements of the technological line are means for impregnating fiberglass with a binder, forming dies and heat treatment furnaces.

A multilayer polymer fiberglass reinforced pipe is obtained as follows.

The first extruder continuously forms a pipe-shell made of polymer materials, which subsequently serves as a support for winding circumferential reinforcing elements onto it.

The claimed method can be carried out using various types of polymers to form the body (matrix) of the shell pipe, in particular using polyethylene, fluoroplastic, polyetherketone, polyethersulfone, polyurethane, thermoplastic vulcanized elastomers, polyamides and other polymers.

It should be noted a distinctive feature of the production line, which provides for the storage of circumferential reinforcement to the side of its longitudinal axis, away from the location line of the main equipment, and the supply of circumferential reinforcement “from the side”, that is, in the direction that is actually perpendicular to the longitudinal axis of the formed product, which makes it possible to ensure practically unlimited in time and volume continuous operation of the production line. The dimensions of the coil with the supply of material of the circumferential reinforcement are not limited, which allows to significantly increase the specified supply of material of the circumferential reinforcement, to increase productivity, to reduce the cost of production.

A fiberglass roving pre-soaked in an epoxy binder is wound from the specified coil installed on the side, passes through a die, forming into a set of a predetermined shape (round, oval, in the form of a ribbon or any other) and passes through a preliminary drying oven (t = 90 ° С ) Further, the dried bundle makes one turn on the bypass roller and enters the stacker roller, which already stacks the bundle in turns on the shell pipe with obtaining a spiral from the circumferential reinforcing elements, applying a clamping force to the bundle for squeezing out an uncured binder from it.

A shell pipe with a spiral of circumferential reinforcing elements is pulled through a final polymerization furnace (t = 130 ° C) to carry out the bonding process. The glued semi-finished product is included in the extrusion head to form a polymer matrix of the outer wall of the multilayer pipe.

When forming the matrix of the outer wall, the molten polymer in front of the extruder mandrel extends along the surface of the heat-resistant non-metallic washer, and the inner and outer surfaces of the molded multilayer polymer reinforced pipe are cooled, which allows to obtain the desired structure of the polymer matrix with the desired ratio of the amorphous and crystalline phase.

The multilayer polymer reinforced pipe obtained by the claimed method as a polymer matrix of the outer wall may contain a thermoplastic or thermoset, in particular a polymer selected from the group consisting of: polyethylene, fluoroplast, polyethereketone, polyethersulfone, polyurethane, polyvinyl chloride, polyamide, thermoplastic vulcanized elastomer.

The combination of various polymeric materials in the manufacture of the shell and the outer layer of the multilayer reinforced pipe expands the range of products. In this case, the shell and the outer layer of the multilayer reinforced pipe can be made of the same polymer or from different types of polymers.

In the described example, the manufactured pipe contains polyethylene as the polymer matrix of the shell pipe and the matrix of the outer layer, its impact strength is not less than 427 kJ / m2, the working pressure is not less than 40 Atm, and the operating temperature range is from minus 50 to + 95 ° C.

For external cooling of the molded polymer reinforced pipe, refrigerant is used, mainly in the form of fog, obtained from compressed air and coolant.

A pulling device acts on the cooled product, advancing the formed pipe to the cutting device. After the cutting device, sequentially in the direction of movement of the formed polymer a reinforced pipe is a roller table equipped with a system for collecting coolant and returning it to the cooling system. The rolling table feeds cut into pieces of a given length of pipe to the installation site of the endings, where at the ends of each segment of the obtained pipe, endings made of polymer unreinforced material are installed. The endings are made in the form of a sleeve with a protrusion at the end located on the inner side of the surface of the sleeve cavity. The inner diameter of the tip corresponds to the outer diameter of the manufactured pipe, and the protrusion closes the exits of the reinforcing elements at the end of the pipe.

The claimed method significantly improves the conditions for the use of tape materials for the circumferential reinforcement of multilayer pipes, since the proposed kinematics of the supply of consumables for transverse reinforcement involves the use of only transverse bending without longitudinal bending of the circumferential reinforcement.

The use of tape district reinforcement, equivalent in cross-sectional area to a round bundle, leads to a decrease in the wall thickness of the pipe and to a corresponding decrease in polymer consumption while maintaining the strength of the composite pipe.

The claimed technology expands the range of products obtained, making it possible to make the production process of multilayer fiberglass pipes continuous.

Moreover, if an increase in the longitudinal stiffness of a multilayer fiberglass pipe is required, the claimed method allows to add longitudinal reinforcement to the transverse circumferential reinforcement. In this case, after the first extruder, coils with fiberglass have been installed on the sides of the processing line after the impregnation step to obtain longitudinal reinforcement elements. Those. a fiberglass roving presoaked in an epoxy binder is wound from the indicated group of coils, passes through a die, forming into bundles, and then dried by an oven (t = 90 ° C). The formed and dried fiberglass harnesses in the form of longitudinal reinforcing elements are guided through peripheral holes in the bearing of the bypass roller and further along the guides they are uniformly moved in the longitudinal direction under the action of the pulling device, entering the extrusion zone moving with extruded pipe shell to exit the device. Before the extrusion zone, the circumferential reinforcement is wound on the longitudinal reinforcing elements by the stacker, as shown above, after which subsequent operations are carried out to obtain a multilayer fiberglass pipe.

A decrease in the stages of the manufacturing process increases the quality of finished products and reduces their cost.

Claims

Claim

1. A method of obtaining a multilayer polymer reinforced pipe, including spiral winding of the circumferential reinforcing elements on the shell and subsequent extrusion deposition of a polymer matrix on them to form the outer layer of the pipe body, cooling and cutting the pipe into segments of a given length,

characterized in that, before the spiral winding operation, the circumferential reinforcing elements are fed to the bypass roller mounted coaxially with the shell and configured to make at least one turn on the surface of said roller coaxially with the spiral windings, and after the bypass roller, the circumferential reinforcing elements sequentially fed first to the guide roller, then to the pressure roller of the stacker,

The circumferential reinforcing elements are made on the basis of non-metallic materials, which are subjected to impregnation with a liquid polymer binder before winding, and after impregnation they are passed through a forming hot die and through a heating zone for preliminary incomplete polymerization of the surface layer of the binder;

the shell in the formation zone of the carcass is sent through an opening in the bearing support of the bypass roller, while the shell and circumferential reinforcing elements are connected to each other under the action of the pressure roller by squeezing the liquid binder from the reinforcing elements and wetting the joint with it; after which the shell with the wound circumferential reinforcing element is fed into the heating zone, where the frame is glued by final polymerization of the binder;

then the casing with the wound circumferential reinforcing elements is directed into the molding cavity of the extruder formed by the specified casing and the outer forming sleeve, while the polymer is injected through the offset head mounted above the casing with the wound circumferential reinforcing elements.

2. The method according to p. 1, characterized in that the casing in the form of a pipe is continuously formed from polymeric materials on an extruder placed in front of the bypass roller and mounted coaxially with it.

3. The method according to p. 1, characterized in that as a shell using a preformed polymer pipe.

4. The method according to any one of p. 2 or 3, characterized in that the shell before entering the inner hole of the bypass roller is pressed with rollers to reduce the outer diameter, and after exiting the bypass roller, it is heated to restore the outer diameter of the shell, then winding onto her district reinforcing elements.

5. The method according to p. 1, characterized in that before the spiral winding operation, longitudinal reinforcing elements based on non-metallic fibers impregnated with a liquid polymer binder are fed to the shell, and after impregnation, the longitudinal reinforcing elements are passed through a forming hot die and through a heating zone for preliminary incomplete polymerization of the surface layer of the binder; while the longitudinal reinforcing is directed to the shell through peripheral holes in the bearing of the bypass roller, and the connection between the longitudinal reinforcing elements and the circumferential reinforcing elements at the points of mutual intersection is effected by the pressure roller during the spiral winding operation.

5. The method according to p. 1, characterized in that fiberglass is used as circumferential reinforcing elements.

6. The method according to p. 5, characterized in that as the circumferential reinforcing elements use fiberglass in the form of rovings, formed into bundles.

7. The method according to p. 5, characterized in that as the circumferential reinforcing elements use fiberglass formed in the form of a tape.

8. The method according to p. 5, characterized in that as a multilayer reinforced pipe receive a multilayer fiberglass pipe.

9. The method according to p. 1, characterized in that after cooling and cutting the manufactured pipe into pieces of a given length at the ends of each pipe piece, ends made of polymer material in the form of a sleeve are installed with a protrusion at the end from the inner surface of the sleeve cavity, while the inner diameter of the tip corresponds to the outer diameter of the manufactured pipe and the protrusion closes the reinforcing elements at the end of the pipe.

10. A multilayer polymer reinforced pipe, characterized in that it is made by the method according to claim 1.