CN115284575A - Three-layer co-extrusion die for preparing glass fiber reinforced pipe - Google Patents

Abstract

The invention relates to a three-layer co-extrusion die for preparing a glass fiber reinforced pipe, which comprises an outer layer die head, a melt spiral die body, a middle layer die body, a spreader cone and a core die which are sequentially sleeved from outside to inside, wherein the outer layer die head, the melt spiral die body, the middle layer die body and the spreader cone are connected into a whole through a screw arranged on a bottom die, a flow passage is arranged between the outer layer die head, the melt spiral die body and the middle layer die body, a gradual annular flow passage is arranged between the middle layer die body and the core die, the spreader cone is provided with a flow guide flow passage, the spreader cone is fixedly connected with the core die, the melt spiral die body is positioned between the outer layer die head and the middle layer die body, a self-orientation spiral groove with a semicircular cross section is formed in the inner surface of the melt spiral die body, the spiral groove and the outer circle of the middle layer die body form a self-spiral orientation flow passage, an inner pre-cooling water passage and an outer precooling water passage are respectively communicated and arranged on the inner side and the outer side of the self-spiral orientation flow passage, and the melt is formed by melting, and cooling in a middle extrusion layer, and the melt extrusion layer, the melt extrusion die has high pressure-resistant grade, compact structure and wide practicability.

Description

Three-layer co-extrusion die for preparing glass fiber reinforced pipe

Technical Field

The invention relates to a multi-layer co-extrusion reinforced pipe die, in particular to a three-layer co-extrusion die for preparing a glass fiber reinforced pipe, which is used for producing a reinforced pipe by glass fibers.

Technical Field

In recent years, the plastic industry in China is developed vigorously, the plastic industry keeps large acceleration every year as a pillar type industry of the light industry, and plastic products are widely applied to industrial production and people's life due to the characteristics of strong plasticity, light weight, stable chemical performance and the like. Extrusion molding products always occupy the first place of plastic products, and coextrusion is an important way to prepare extruded profiles with composite material layers.

The polyethylene pipe produced by extrusion occupies a large share in the pipe market due to the advantages of low price, high yield, small pollution and the like, but the polyethylene pipe has the defects of poor rigidity, small stretching ratio, large creep and the like, thereby affecting the service life of the polyethylene pipe.

Plastic articles of a single material have been increasingly difficult to meet market and practical needs, and thus composite materials have been rapidly developed. The glass fiber is used as a filler, and has the advantages of light weight, hardness, corrosion resistance, high strength, good anti-aging effect and the like, so that the glass fiber is widely applied to extruded products. However, the existing glass fiber reinforced pipe has the problems of non-uniform distribution of glass fibers, inconsistent orientation and the like due to imperfect preparation mode, and is increasingly difficult to meet the requirements of modern industry.

Publication No. CN205044123U discloses the utility model of "a three-layer is crowded mould altogether", and this utility model discloses a three-layer is crowded mould structure altogether, and its purpose provides a novel three-layer is crowded mould altogether, can combine the three-layer melt together well. However, as the three layers are all extruded by common axial stretching, the obtained pipe has the problems of poor tensile resistance, short service life and the like. If the mixed material of the glass fiber and the PE is processed by using the die, the problems of disordered orientation of the glass fiber and the like are caused, so that the obtained pipe cannot achieve the required reinforcing effect.

Publication No. CN102364189A discloses "a composite plastic pipe", the pipe wall of which comprises three layers of structures, namely an outer layer metal pipe, a sandwich glass fiber pipe and an inner layer plastic pipe. Wherein, the inner layer and the outer layer of the sandwich glass fiber pipe are respectively coated with a glue layer, so that the sandwich glass fiber pipe, the outer layer metal pipe and the inner layer plastic pipe are tightly bonded into a whole. Its purpose is to increase the strength and rigidity of plastic pipe and prolong its service life. However, the composite pipe is formed by three layers of three materials respectively and finally bonded by the glue layer, so that the composite pipe has the defects of complex preparation method, easy generation of internal stress of the three layers of different materials, deformation of pipe diameter caused by different expansion properties of the three layers of materials and the like, and the expected enhancement effect and the service life of the composite pipe are difficult to achieve.

Publication No. CN103527862A proposes a glass fiber reinforced polyethylene composite pipe and a preparation method thereof, wherein the preparation method of the glass fiber reinforced polyethylene composite pipe comprises the steps of arranging a glass fiber reinforced layer between a polyethylene outer pipe and a polyethylene inner pipe, and winding one or more layers of glass fiber cloth or glass fiber wires on a common high-density polyethylene pipe, so as to improve the creep problem of the polyethylene pipe. However, in the pipe prepared by the method, the stress concentration phenomenon is easily generated in the internal banded glass fiber in the use process, so that the glass fiber is broken, and the expected reinforcing effect cannot be achieved; in addition, the preparation method of the pipe is relatively complex, the inner layer pipe is extruded and then wound with a glass fiber tape with a certain angle outside the inner layer pipe through a winding machine, and then the outer layer pipe is extruded after the glass fiber is wound and is covered outside the wound glass fiber tape, so that the pipe is called as an outer layer pipe. In addition, the fiberglass tape requires separate production equipment. The most important problem is that the winding wheel of the winding machine winds a certain length of glass fiber ribbon, so that the winding wheel needs to be replaced periodically during the production of the tube, thereby possibly causing a stop or a waste tube.

Disclosure of Invention

The invention aims to provide a three-layer co-extrusion die for preparing a glass fiber reinforced pipe, which aims to solve the problems in the technical background.

In order to achieve the purpose, the technical scheme provided by the invention is as follows.

A three-layer co-extrusion die for preparing a glass fiber reinforced pipe comprises an outer layer die head, a melt spiral die body, a middle layer die body, a spreader cone and a core die which are sequentially sleeved from outside to inside, wherein the outer layer die head, the melt spiral die body, the middle layer die body and the spreader cone are connected into a whole through a screw arranged on a bottom die, a runner is formed between the melt spiral die body and the middle layer die body, a gradual annular runner is formed between the middle layer die body and the core die, a plurality of symmetrically distributed diversion runners are arranged in the spreader cone and are communicated with the gradual annular runner, the spreader cone is fixedly connected with the core die, a self-orientation spiral groove with a semicircular cross section is formed in the inner surface of the melt spiral die body, the spiral groove and the outer circle of the middle layer die body form a self-spiral orientation runner, cooling water channels are respectively arranged on the melt spiral die body and the middle layer die body, and the cooling water channels are used for pre-cooling materials flowing through the spiral orientation runner.

The hole of outer die head is provided with: the outer layer die head positioning hole is in a circular section, the aperture of the outer layer die head positioning hole is larger than that of the forming hole, the outer layer die head positioning hole is transited into the forming hole through a tapered slotted hole with gradually reduced sectional area, the melt spiral die body is provided with an outer circle, the upper end of the outer circle is provided with an outer conical surface in transition connection, a tapered annular outer layer material flow passage is formed between the tapered slotted hole and the outer conical surface of the melt spiral die body, the periphery of the core die is provided with a forming outer circle, a forming outer conical surface and a gradually changed outer conical surface, the forming outer circle is a cylindrical surface with equal diameter, the outer diameter of the forming outer circle is the largest, the forming outer circle, the forming outer conical surface and the gradually changed outer conical surface are in transition connection in sequence, the cross section is gradually reduced, the melt spiral die body, the outer layer die head and the middle layer die body sequentially penetrate through the bottom die body and the concentric connecting flanges of the melt spiral die body and the middle layer die body through bolts distributed on the circumference to be connected, a sealing groove is arranged on the contact surface, a sealing ring is arranged in a leakage prevention manner, and the bottom die body is provided with a middle layer material interface and an inner layer material interface; the middle layer die body is internally provided with a pore passage connected with the middle layer material interface, the pore passage is connected with the spiral orientation flow passage, the outer layer material interface is arranged on the outer layer die head, and the inner layer material interface is connected with the plurality of diversion flow passages.

The inner surface of the melt spiral die body is provided with 3-10 spiral grooves, the axial length of each spiral groove is 300-500 mm, and the helix angle is 30-35 degrees.

The tail end of the spiral orientation flow passage is connected with a shaping compression section flow passage, the gradual change annular flow passage firstly converges on the shaping compression section flow passage, and the tapered annular outer layer material flow passage converges on the shaping compression section flow passage.

The melt spiral die body is provided with an inner annular surface of a conical surface at the termination position of the spiral groove, the inner annular surface is transitionally provided with an extrusion molding annular surface, and the shaping compression section flow channel is formed by respectively matching the inner annular surface of the melt spiral die body, the extrusion molding annular surface and a molding hole of the outer die head with a molding excircle of the core die.

The middle layer die body is provided with an upper inner cone ring surface and an inner circular hole in transitional connection, the upper inner cone ring surface of the middle layer die body is matched with the forming outer conical surface, the inner circular hole of the middle layer die body is aligned with the gradual change outer conical surface, the upper inner cone ring surface and the inner circular hole of the middle layer die body respectively form a tapered annular inner layer material flow channel with the forming outer conical surface and the gradual change outer conical surface of the core die, and the tapered annular inner layer material flow channel is a gradual change annular flow channel with a gradually changed cross-sectional area.

The vertex angle Ra of the melt spiral mould body is 30-40 degrees.

The vertex angle Rb of the middle layer mold body is 20-25 degrees.

The length of the spiral orientation section is larger than that of the shaping compression section after orientation.

In the technical scheme, the self-orientation spiral reinforcing layer is provided with the glass fiber mixed material, when the molten material mixed with the glass fiber is extruded through the middle layer, the mixture of the melt and the glass fiber in the melt spiral die body generates the self-orientation property of 45 degrees along the extrusion circumferential direction, the melt mixing and cooling forming of the melt in the middle extrusion layer are realized, the pressure-resistant grade of the pipe is greatly improved, and the three-layer extrusion die is compact in structure and wide in practicability.

Drawings

FIG. 1 is a schematic diagram of a three-layer extrusion die of the present invention;

FIG. 2 is a schematic view of the elevation angle section structure of a spiral groove in the melt spiral mold body according to the present invention;

FIG. 3 is a schematic cross-sectional view of a fracture of a spiral groove in the melt spiral die body of the present invention;

FIG. 4 is a schematic diagram of an outer layer die structure according to the present invention;

fig. 5 is a schematic view of a core mold structure of the present invention.

The device comprises a core die 1, an outer die 2, an outer material port 3, a melt spiral die 4, a middle die 5, a bottom die 6, a first outer cooling water channel port 7, a first middle material port 8, a first inner cooling water channel port 9, a diverging cone 10, an inner material port 11, a spiral groove 12, a conical surface 13, a forming section 14, a second outer cooling water channel port 15, a second middle material port 16, a second inner cooling water channel port 17, a spiral orientation section runner 18, a 19-shaping compression section runner, a 101-shaping excircle, a 102-shaping outer conical surface, a 103-gradual change outer conical surface, a 201-shaping hole, a 202-conical slotted hole and an outer die positioning hole 203.

Detailed description of the preferred embodiments

The following further describes the embodiments of the present invention.

Referring to fig. 1-5, a three-layer co-extrusion mold for preparing a glass fiber reinforced pipe comprises an outer layer mold head 2, a melt spiral mold body 4, a middle layer mold body 5, a spreader 10, a core mold 1 and a bottom mold 6 which are sequentially sleeved from outside to inside.

Outer die head 2, the melt spiral mould body 4 and the middle-layer mould body 5 are concentric circle type structures, and the outer circle bottom of the melt spiral mould body 4 and the middle-layer mould body 5 is provided with a concentric connecting flange, so that the thickness of a material layer can be greatly stabilized, and the assembly difficulty is reduced.

The inner hole of the outer layer die head 2 is provided with: shaping hole 201, toper slotted hole 202, outer die head locating hole 203, shaping hole 201, outer die head locating hole 203 is the ring shape cross-section, outer die head locating hole 203 aperture is greater than shaping hole 201 aperture, outer die head locating hole 203 passes through the toper slotted hole 202 transition that the sectional area diminishes gradually into shaping hole 201, outer die head locating hole 203 is used for with the external circle location of the fuse-element spiral mould body 4 sealed, fuse-element spiral mould body 4 is provided with the excircle, the excircle upper end is provided with transitional coupling's the outer conical surface, form the annular outer layer material runner of toper between the outer conical surface of toper slotted hole 202 and the fuse-element spiral mould body 4, the outer layer material is through the annular outer layer material runner of toper that outer material interface 3 intercommunication that outer die head 2 set up gets into in the outer die head 2.

As shown in fig. 1 and 5, the outer periphery of the core mold 1 is provided with a molding outer circle 101, a molding outer conical surface 102, and a gradual outer conical surface 103, the molding outer circle 101 is an isodiametric cylindrical surface, the outer diameter of the molding outer circle 101 is the largest, and the molding outer circle 101, the molding outer conical surface 102, and the gradual outer conical surface 103 are in transition connection in sequence and have gradually smaller cross sections.

3-10 spiral grooves 12 are arranged on the inner wall of the self-oriented interlayer melt spiral mold body 4, and the helix angle is 30-35 degrees; in order to ensure that the orientation of the glass fiber in the molten material is sufficient, the axial length of the spiral groove 12 is 300-500 mm, the melt spiral mold body 4 is positioned at the termination position of the spiral groove 12 and is provided with an inner annular surface of a conical surface 13, the inner annular surface is transitionally provided with an extrusion molding annular surface 14, a molding compression section runner 19 for molding the molten material containing the glass fiber is formed between the termination position of the spiral groove 12 and a confluence position, the molding compression section runner 19 is formed by matching the inner annular surface of the melt spiral mold body 4, the extrusion molding annular surface 14 and a molding hole 201 of the outer layer mold head 2 with a molding excircle 101 of the core mold 1 respectively, the excircle surface of the middle layer mold body 5 and the spiral groove 12 of the melt spiral mold body 4 form a spiral orientation runner 18, the middle-layer die body 5 is provided with an upper inner cone ring surface and an inner circular hole in transitional connection, the upper inner cone ring surface of the middle-layer die body 5 is matched with the forming outer conical surface 102, the inner circular hole of the middle-layer die body 5 is aligned with the gradual change outer conical surface 103, the upper inner cone ring surface and the inner circular hole of the middle-layer die body 5 respectively form a conical annular inner layer material flow channel with the forming outer conical surface 102 and the gradual change outer conical surface 103 of the core die 1, the shaping compression section flow channel 19 is a shaping compression section, the spiral orientation flow channel 18 is a spiral orientation section, the distance of the spiral orientation section generated by the opened spiral groove 12 is longer, the distance of the shaping compression section 19 after orientation is shorter, the conical annular inner layer material flow channel and the spiral orientation flow channel 18 firstly converge on the shaping compression section flow channel 19, and the conical annular outer layer material flow channel converges on the shaping compression section flow channel 19.

An external cooling water channel is formed in the melt spiral mold body 4 and used for pre-cooling the glass fiber molten material flowing through the spiral orientation section, and the bottom mold 6 is provided with a first external cooling water channel connector 7 and a second external cooling water channel connector 15 which are respectively connected with the external cooling water channels for receiving/receiving cooling water.

The melt spiral die body 4, the outer layer die head 2 and the middle layer die body 5 sequentially penetrate through the bottom die 6 and concentric connecting flanges of the melt spiral die body 4 and the middle layer die body 5 through 6-8 countersunk head bolts distributed on the circumference to be connected, a sealing groove is arranged on a contact surface, and a built-in sealing ring is arranged to prevent material leakage.

The bottom die 6 is provided with a first middle layer material interface 8, a second middle layer material interface 16 and an inner layer material interface 11; the middle layer mold body 5 is internally provided with a pore canal which is connected with a first middle layer material interface 8 and a second middle layer material interface 16, and the pore canal is connected with a spiral orientation runner 18.

An inner cooling water channel is formed in the middle layer mold body 5 and used for pre-cooling the glass fiber melting material flowing through the spiral orientation section; the bottom die 6 is provided with a first inner cooling water channel connector 9 and a second inner cooling water channel connector 17 which are respectively connected with an inner cooling water channel to receive cooling water, the inner cooling water channel and the outer cooling water channel form a symmetrical layout, so that the cooling is uniform, the normal orientation flow of the glass fiber melting material is prevented from being influenced by the generation of internal stress, and the oriented glass fiber melting material can be kept in an orientation state better.

The outer circle of the diffluence cone 10 is matched and positioned with the inner circular hole of the middle layer die body 5, two end faces are respectively connected with the bottom die 6 and the core die 1 in a butt-clamping manner, a plurality of symmetrically distributed diversion runners are arranged in the diffluence cone 10, the inner layer material interface 11 is connected with a common inlet connecting point of the diversion runners, and outlets of the diversion runners are distributed and connected with the conical annular inner layer material runners.

The core mold 1, the spreader cone 10 and the bottom mold 6 are connected through 4-6 countersunk head bolts distributed on the circumference, a sealing groove is arranged on the contact surface, and a sealing ring is arranged in the sealing groove to prevent material leakage.

The taper annular inner layer material flow channel between the middle layer die body 5 and the core die 1 is a gradual change annular flow channel with gradually changed cross sectional area, the compression ratio of the die can be selected between 4-9, the gradually reduced cross sectional area of the flow channel enables material flow to establish certain back pressure, the material is enabled to be compactly accumulated, the material is enabled to be easy to shape, the product quality of an extruded pipe is enabled to be better, the surface is smooth, and the defects of air holes inside the pipe are reduced.

The structure of the implemented melt spiral die body 4 adopts staggered confluence at the confluence part of the die head part; wherein, the middle layer material, namely the glass fiber melt mixing material, is converged with the inner layer material firstly, and then converged with the outer layer material; the synchronous confluence can cause the inner and outer material layers to simultaneously impact the fiber reinforced mixed melt which is self-oriented by the spiral groove, so as to interfere the orientation flow of the fiber reinforced mixed melt, thereby reducing the orientation effect of the glass fiber in the melt; the staggered confluence can reduce the de-orientation effect during confluence, so that the melt and the glass fiber mixture can generate 45-degree orientation along the extrusion circumferential direction after being converged.

The outer layer die head 2, the melt spiral die body 4, the middle layer die body 5, the spreader cone 10, the core die 1 and the bottom die 6 are all geometric bodies with regular shapes and reasonable internal pore distribution, and the processing can be finished by adopting general mechanical processing means such as vehicle milling, grinding and drilling.

The three-layer extrusion die has a compact structure, and all parts are regular and symmetrical in shape, so that heat transfer is uniform; all parts are connected by bolts, and the assembly and disassembly are convenient.

The middle layer glass fiber melt-mixing material implemented is short fiber reinforced composite (SFT) and requires that the length of glass fibers uniformly dispersed in the PE matrix does not exceed 12mm at the maximum. The glass fiber for the interlayer compound of the present invention is determined to have a length of 1.2mm to 3mm in consideration of the production cost of the glass fiber, the degree of compatibility with the matrix and the ability to achieve sufficient reinforcing effect.

The three-layer extrusion die of the self-oriented glass fiber reinforced layer can ensure that the glass fiber can retain the spiral orientation to the maximum extent when converging, the intersection angle when the outer layer material and the middle layer material converge is 30-40 degrees, and the intersection angle when the inner layer material and the middle layer material converge is 20-25 degrees.

The technical scheme of the invention is further explained by specific embodiments in the following with reference to the attached drawings.

Example one

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings. These drawings are simplified schematic views, and merely illustrate the basic structure of the present invention in a schematic manner, and therefore, only show the components related to the present invention.

The three-layer co-extrusion die for preparing the glass fiber reinforced pipe shown in the attached drawing 1 comprises a core die 1, an outer die head 2, an outer layer material interface 3, a melt spiral die body 4, a middle layer die body 5, a bottom die 6, a first outer cooling water channel interface 7, a second outer cooling water channel interface 15, a first middle layer material interface 8, a second middle layer material interface 16, a first inner cooling water channel interface 9, a second inner cooling water channel interface 17, a spreader cone 10 and an inner layer material interface 11.

The three-layer co-extrusion die is characterized in that a mixed molten inner-layer material enters a bottom die 6 from an inner-layer material interface 11, and after a columnar flow is split by a spreader cone 10, the columnar flow passes through a gradual change annular flow channel between a middle-layer die body 5 and a core die 1 and converges with a glass fiber molten mixed material after the middle layer is self-oriented at an intersection angle of 20-25 degrees; the middle-layer glass fiber melt mixed material enters a bottom die 6 from a first middle-layer material feeding port 8 and a second middle-layer material interface 16, flows in a columnar flow in a middle-layer die body 5, then passes through a self-orientation spiral groove 12 with a spiral rising angle of 30-35 degrees formed by a melt spiral die body 4 and the middle-layer die body 5, so that the glass fiber melt mixed material is oriented along the direction of the spiral groove 12, and in order to prevent the change of the orientation angle of the glass fiber melt mixed material, a conical surface 13 is arranged for the transition from a spiral orientation section to a shaping compression section so as to ensure the orientation angle of the glass fiber; the mixed melted outer layer material flows into the outer layer die head 2 from the outer layer material interface 3, flows in a columnar shape when entering the outer layer die head 2, changes into an annular flow when passing through a conical gap between the outer layer die head 2 and the melt spiral die body 4, and converges with the other two layers of materials at an intersection angle of 30 degrees.

The outer layer of the three-layer co-extrusion pipe produced by the invention is a wear-resistant PE layer, and cross-linked polyethylene, high molecular weight polyethylene and the like can be mixed in a PE matrix for modification, so that the scratch resistance and wear resistance of the outermost layer are enhanced.

The middle layer of the three-layer co-extruded pipe produced by the invention is a self-oriented glass fiber reinforced PE layer, and the glass fiber is an excellent inorganic non-metallic material and has the characteristics of good insulativity, good heat resistance, high mechanical strength and the like. PE (polyethylene) is used as a matrix of the composite material; adding maleic anhydride grafted polyethylene into the mixed material, wherein acrylic acid grafted polyethylene is used as a compatibilizer; adding a silane coupling agent and taking an aluminate coupling agent as an activating agent to activate the surface of the glass fiber, so that the glass fiber has better compatibility with a polyethylene matrix; color masterbatch can also be added to improve the compounding fastness.

The middle self-orientation glass fiber reinforced layer of the three-layer co-extrusion pipe produced by the three-layer co-extrusion die is manufactured by a co-extrusion process with other two layers, so that a common bonding coating between three layers of the glass fiber reinforced pipe on the market is not available, the internal stress of the pipe is greatly reduced, and the service life of the pipe is prolonged; the three-layer co-extrusion pipe produced by the three-layer co-extrusion die can be used at the temperature of-40-70 ℃ for a long time, has excellent frost resistance, does not crack due to the fact that the three layers are not bonded by the glue layer, and meanwhile, the glass fiber endows the pipe with higher tensile elastic modulus and bending elastic modulus, and does not freeze and crack when the pipe is frozen above-20 ℃. Compared with other similar products, the overall mechanical performance is improved by more than 20%.

The middle layer produced by the three-layer co-extrusion die is the three-layer co-extrusion pipe with the self-orientation glass fiber reinforced layer, the glass fibers in the obtained finished product are oriented at 45 degrees along the extrusion circumferential direction, and the tensile strength of the pipe in the circumferential direction and the axial direction is increased, so that the pressure-resistant grade of the pipe is greatly improved, and the service life of the pipe is prolonged.

Example two

The technical solution of the present invention is further described below by way of examples with reference to the accompanying drawings. These drawings are simplified schematic diagrams each illustrating the basic structure of the present invention only in a schematic manner, and therefore, only the constitution related to the present invention is shown.

As shown in fig. 1-3, a three-layer co-extrusion mold for preparing a glass fiber reinforced pipe comprises a core mold 1, an outer-layer mold head 2, an outer-layer material interface 3, a melt spiral mold body 4, a middle-layer mold body 5, a bottom mold 6, a first outer cooling water channel interface 7, a second outer cooling water channel interface 15, a first middle-layer material interface 8, a second middle-layer material interface 16, a first inner cooling water channel interface 9, a second inner cooling water channel interface 17, a spreader cone 10 and an inner-layer material interface 11.

The three-layer co-extrusion die is characterized in that a mixed molten inner-layer material enters a bottom die 6 from an inner-layer material interface 11, a columnar flow is divided by a flow dividing cone 10, and then flows with a glass fiber molten mixed material after the middle layer self-orientation through a gradual change annular flow passage between a middle-layer die body 5 and a core die 1 at an intersection angle of 20-25 degrees; the middle-layer glass fiber melting mixed material enters a bottom die 6 from a first middle-layer material interface 8 and a second middle-layer material interface 16, flows in a columnar flow in a middle-layer die body 5, then passes through a self-orientation spiral groove 12 with a spiral rising angle of 30-35 degrees formed by a melt spiral die body 4 and the middle-layer die body 5, so that the glass fiber melting mixed material is oriented along the direction of the spiral groove 12, and in order to prevent the change of the orientation angle of the glass fiber melting mixed material, a conical surface 13 is arranged for the transition from a spiral orientation section to a shaping compression section so as to ensure the orientation angle of the glass fiber; the mixed melted outer layer material flows into the outer layer die head 2 from the outer layer material interface 3, flows in a columnar shape when entering the outer layer die head 2, changes into an annular flow when passing through a conical gap between the outer layer die head 2 and the melt spiral die body 4, and converges with the other two layers of materials at an intersection angle of 30 degrees.

The outer layer of the three-layer co-extrusion pipe produced by the invention is a wear-resistant PP layer, and a wear-resistant agent can be mixed in a PP matrix, so that the scratch resistance and wear resistance of the outermost layer are enhanced.

The middle layer of the three-layer co-extrusion pipe produced by the invention is a self-oriented glass fiber reinforced PP layer, and the glass fiber is an excellent inorganic non-metallic material and has the characteristics of good insulativity, good heat resistance, high mechanical strength and the like. PP (polypropylene) is used as a matrix of the composite material; adding maleic anhydride grafted polypropylene as a compatibilizer into the mixed material; adding a silane coupling agent and taking an aluminate coupling agent as an activating agent to activate the surface of the glass fiber, so that the glass fiber has better compatibility with a polypropylene matrix; color masterbatch can also be added to improve the compounding fastness.

The middle self-orientation glass fiber reinforced layer of the three-layer co-extrusion pipe produced by the three-layer co-extrusion die is manufactured by a co-extrusion process with other two layers, so that a common three-layer gluing coating of the glass fiber reinforced pipe on the market is not provided, the internal stress of the pipe is greatly reduced, and the service life of the pipe is prolonged; the three-layer co-extrusion pipe produced by the three-layer co-extrusion die can be used at the temperature of-15-70 ℃ for a long time, has excellent wear resistance, does not crack due to the fact that the three layers are not bonded by the glue layer, and meanwhile, the glass fiber endows the pipe with higher tensile elastic modulus and bending elastic modulus, and does not freeze and crack when the pipe is frozen in the temperature of more than-5 ℃. Compared with other similar products, the overall mechanical property is improved by more than 20%.

The middle layer produced by the three-layer co-extrusion die is the three-layer co-extrusion pipe with the self-orientation glass fiber reinforced layer, the glass fibers in the obtained finished product are oriented at 45 degrees along the extrusion circumferential direction, and the tensile strength of the pipe in the circumferential direction and the axial direction is increased, so that the pressure-resistant grade of the pipe is greatly improved, and the service life of the pipe is prolonged.

The embodiments are merely illustrative, the technical scope of the claims of the present invention is not limited to the content of the description, and those skilled in the art can make various modifications or additions to the embodiments or substitute the same, without departing from the spirit of the present invention or exceeding the scope of the claims.

Although the terms of the core mold 1, the outer layer mold head 2, the outer layer material interface 3, the melt spiral mold body 4, the middle layer mold body 5, the bottom mold 6, the first outer cooling water channel interface 7, the first middle layer material interface 8, the first inner cooling water channel interface 9, the diverging cone 10, the inner layer material interface 11, the spiral groove 12, the conical surface 13, the molding ring surface 14, the second outer cooling water channel interface 15, the second middle layer material interface 16, the second inner cooling water channel interface 17, and the like are used more frequently in the present invention, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to the spirit of the present invention.

Claims (9)

1. The utility model provides a three-layer is crowded mould altogether of preparation glass fiber reinforced pipe material, includes by outer die head (2), the melt spiral mould body (4), the middle level mould body (5), the reposition of redundant personnel awl (10), mandrel (1) that cup joint in proper order in to, outer die head (2), the melt spiral mould body (4), the middle level mould body (5), reposition of redundant personnel awl (10) through the screw connection of die block (6) setting in an organic whole, its characterized in that: runners are formed among the outer layer die head (2), the melt spiral die body (4) and the middle layer die body (5), gradual change annular runners are formed between the middle layer die body (5) and the core die (1), a plurality of symmetrically distributed flow guide runners are arranged in the spreader cone (10), the flow guide runners are communicated with the gradual change annular runners, the spreader cone (10) is fixedly connected with the core die (1), a self-orientation spiral groove (12) with a semicircular cross section is formed in the inner surface of the melt spiral die body (4), the spiral groove (12) and the outer circle of the middle layer die body (5) form a self-spiral orientation runner (18), and cooling water channels are respectively arranged on the melt spiral die body (4) and the middle layer die body (5) and are used for pre-cooling materials flowing through the spiral orientation runner (18).

2. The three-layer co-extrusion mold for preparing glass fiber reinforced pipe material as claimed in claim 1, wherein: the inner hole of the outer layer die head (2) is provided with: a forming hole (201), a tapered groove hole (202) and an outer layer die head positioning hole (203), wherein the forming hole (201) and the outer layer die head positioning hole (203) are circular sections, the aperture of the outer layer die head positioning hole (203) is larger than that of the forming hole (201), the outer layer die head positioning hole (203) is transited into the forming hole (201) through the tapered groove hole (202) with gradually reduced sectional area, the melt spiral die body (4) is provided with an excircle, the upper end of the excircle is provided with an outer conical surface in transition connection, a conical annular outer layer material flow passage is formed between the conical groove hole (202) and the outer conical surface of the melt spiral die body (4), the outer periphery of the core mold (1) is provided with a forming excircle (101), a forming outer conical surface (102) and a gradual change outer conical surface (103), the forming excircle (101) is an isometric cylindrical surface, the outer diameter of the forming excircle (101) is the largest, the forming excircle (101), the forming outer conical surface (102) and the gradual change outer conical surface (103) are sequentially connected in a transition way, the cross section of the forming excircle, the forming outer conical surface and the gradual change outer conical surface are gradually reduced, the melt spiral mold body (4), the outer layer mold head (2) and the middle layer mold body (5) are connected by sequentially penetrating through concentric connecting flanges of the bottom mold (6), the melt spiral mold body (4) and the middle layer mold body (5) through circumferentially distributed bolts, a sealing groove is arranged on the contact surface, a sealing ring is arranged in the sealing groove to prevent material leakage, and a middle-layer material interface and an inner-layer material interface (11) are arranged on the bottom die (6); the middle layer die body (5) is internally provided with a pore passage connected with a middle layer material interface, the pore passage is connected with a spiral orientation flow passage (18), the outer layer die head (2) is provided with an outer layer material interface (3), and the inner layer material interface (11) is connected with a plurality of flow guide flow passages.

3. The three-layer co-extrusion mold for preparing the glass fiber reinforced pipe material as claimed in claim 2, wherein: the inner surface of the melt spiral die body (4) is provided with 3-10 spiral grooves (12), the axial length of each spiral groove (12) is 300-500 mm, and the helix angle is 30-35 degrees.

4. The three-layer co-extrusion mold for preparing the glass fiber reinforced pipe material as claimed in claim 3, wherein: the tail end of the spiral orientation flow channel (18) is connected with a shaping compression section flow channel (19), the gradual change annular flow channel firstly converges on the shaping compression section flow channel (19), and the conical annular outer layer material flow channel converges on the shaping compression section flow channel (19).

5. The three-layer co-extrusion mold for preparing the glass fiber reinforced pipe material as claimed in claim 4, wherein: the melt spiral die body (4) is located at the end position of the spiral groove (12) and is provided with an inner annular surface of the conical surface (13), the inner annular surface is transitionally provided with an extrusion molding annular surface (14), and the sizing compression section flow channel (19) is formed by respectively matching the inner annular surface of the melt spiral die body (4), the extrusion molding annular surface (14) and a molding hole (201) of the outer layer die head (2) with a molding excircle (101) of the core die (1).

6. The three-layer co-extrusion mold for preparing the glass fiber reinforced pipe material as claimed in claim 4, wherein: the middle-layer die body (5) is provided with an upper inner cone ring surface and a transitional inner circular hole, the upper inner cone ring surface of the middle-layer die body (5) is matched with the forming outer conical surface (102), the inner circular hole of the middle-layer die body (5) is aligned with the gradual change outer conical surface (103), the upper inner cone ring surface and the inner circular hole of the middle-layer die body (5) form a tapered annular inner material flow channel with the forming outer conical surface (102) and the gradual change outer conical surface (103) of the core die (1) respectively, and the tapered annular inner material flow channel is a gradual change annular flow channel with gradually changed cross-sectional area.

7. The triple co-extrusion die for preparing the glass fiber reinforced pipe according to any one of claims 1 to 5, wherein: the vertex angle Ra of the melt spiral mold body (4) is 30-40 degrees.

8. The triple co-extrusion die for preparing the glass fiber reinforced pipe material according to any one of claims 1 to 5, wherein: the vertex angle Rb of the middle layer mold body (5) is 20-25 degrees.

9. The three-layer co-extrusion mold for preparing the glass fiber reinforced pipe material as claimed in claim 4, wherein: the length of the spiral orientation section is larger than that of the shaping compression section after orientation.

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